BOSTON — Investigators poring over photos and video from the Boston Marathon bombing have a department-store surveillance-camera image of a man dropping off a bag at the scene of the one of the blasts, a top city politician said Wednesday.

City Council President Stephen Murphy, who said he was briefed by members of the Boston Police Department, said he does not know if investigators know the man's name. He said officers are chasing leads that could take them to the suspect.

"They may be on the verge of arresting someone and that's good," he said.

Separately, a law enforcement official who spoke to The Associated Press on condition of anonymity and was not authorized to discuss the case publicly confirmed only that investigators had an image of a potential suspect but did not know his identity.

The twin bomb blasts Monday near the finish line of the world's most famous foot race killed three people and wounded more than 170, tearing off limbs in a hail of shrapnel.

Law enforcement agencies pleaded for the public to come forward with photos, videos or any information that might help them solve the case, and they gathered surveillance video from businesses around the finish line.

The bombs are believed to have been fashioned out of ordinary kitchen pressure cookers packed with explosives, nails, ball bearings and metal shards designed to maim. Investigators suspect the bombs were hidden in black duffel bags and left on the ground.

As a result, they were looking for images of someone lugging a dark, heavy bag.

"One of the department stores down on Boylston Street submitted video system which has confirmed that a suspect is seen dropping a bag near the point of the second explosion and heading off," Murphy said.

Murphy said he was told investigators have matched information from the surveillance footage with witness descriptions of someone leaving the scene.

Earlier in the day, several news organizations, citing unidentified sources, reported that a video surveillance camera at a Lord & Taylor department store midway between the two blast sites showed a suspect with a backpack near the finish line.

The news came with Boston in a state of high excitement over conflicting information on whether a suspect was in custody.

A law enforcement official briefed on the investigation told the AP around midday that a suspect was in custody. The official, who was not authorized to divulge details of the investigation, said the suspect was expected in federal court.

But the FBI and the U.S. attorney's office in Boston said no arrests had been made.

"Contrary to widespread reporting, there have been no arrests made in connection with the Boston Marathon attack," the FBI said in a statement. "Over the past day and a half, there have been a number of press reports based on information from unofficial sources that has been inaccurate. Since these stories often have unintended consequences, we ask the media, particularly at this early stage of the investigation, to exercise caution and attempt to verify information through appropriate official channels before reporting."

The official who spoke to the AP about someone being taken into custody stood by the information even after it was disputed.

Scores of victims remained hospitalized, many with grievous injuries. Fourteen were listed in critical condition. Doctors who treated the wounded corroborated reports that the bombs were packed with shrapnel and blew up close to the ground.

The chief of trauma surgery at Boston Medical Center said most of the injuries his hospital treated were to the legs.

"We have a lot of lower-extremity injuries, so I think the damage was low to the ground and wasn't up," Dr. Peter Burke said. "The patients who do have head injuries were blown into things or were hit by fragments that went up."

The blasts killed 8-year-old Martin Richard of Boston and 29-year-old Krystle Campbell of Medford. The Shenyang Evening News, a state-run Chinese newspaper, identified the third victim as Lu Lingzi. She was a graduate student at Boston University.

A bomb threat forced the evacuation of the courthouse Wednesday midafternoon, the U.S. Marshals Service said, and security officials swept the area. Employees were allowed back in about an hour later.


EARLIER REPORT

Federal officials denied a suspect was under arrest Wednesday in the Boston Marathon bombings.

A law enforcement official briefed on the investigation told The Associated Press earlier in the day that a suspect was in custody. The FBI and the U.S. attorney's office in Boston said that no arrests had been made.

The official who spoke to the AP did so on condition of anonymity and stood by the information even after it was disputed. The official, who was not authorized to divulge details of the investigation, had said the suspect was expected in federal court in Boston.

Reporters and police converged at the courthouse.

Several media outlets reported that a suspect had been identified from surveillance video taken at a Lord & Taylor store between the sites of the two bomb blasts, which killed three people and wounded more than 170.

A news briefing was scheduled later Wednesday.

"Contrary to widespread reporting, there have been no arrests made in connection with the Boston Marathon attack," the FBI said in a statement. "Over the past day and a half, there have been a number of press reports based on information from unofficial sources that has been inaccurate. Since these stories often have unintended consequences, we ask the media, particularly at this early stage of the investigation, to exercise caution and attempt to verify information through appropriate official channels before reporting."

Law enforcement agencies had earlier pleaded for the public to come forward with photos, videos or any information that might help them solve the twin bombings. Police also gathered surveillance video from businesses around the finish line.

The bombs were made from ordinary kitchen pressure cookers packed with explosives, nails and ball bearings to inflict maximum carnage, investigators and others close to the case said. But the FBI said nobody had claimed responsibility.

Investigators in white jumpsuits had fanned out across the streets, rooftops and awnings around the blast site in search of clues on Wednesday. They combed through debris amid the toppled orange sports drink dispensers, trash cans and sleeves of plastic cups strewn across the street at the marathon's finish line.

President Barack Obama branded the attack an act of terrorism. Obama plans to attend an interfaith service Thursday in the victims' honor in Boston.

Scores of victims of the Boston bombing remained in hospitals, many with grievous injuries. Doctors who treated the wounded corroborated reports that the bombs were packed with shrapnel intended to cause mayhem. In addition to the 5-year-old child, a 9-year-old girl and 10-year-old boy were among 17 victims listed in critical condition.

The trauma surgery chief at Boston Medical Center says most of the injuries his hospital treated after the marathon bombings were to the legs.

"We have a lot of lower extremity injuries, so I think the damage was low to the ground and wasn't up," Dr. Peter Burke said. "The patients who do have head injuries were blown into things or were hit by fragments that went up."

Dozens of patients have been released from hospitals around the Boston area.

At Massachusetts General Hospital, all four amputations performed there were above the knee, with no hope of saving more of the legs, said Dr. George Velmahos, chief of trauma surgery.

"It wasn't a hard decision to make," he said Tuesday. "We just completed the ugly job that the bomb did."

The bombs exploded 10 or more seconds apart, tearing off victims' limbs and spattering streets with blood. The blasts near the finish line instantly turned the festive race into a hellish scene of confusion, horror and heroics.

The blasts killed 8-year-old Martin Richard, of Boston, and 29-year-old Krystle Campbell, of Medford. The Shenyang Evening News, a state-run Chinese newspaper, identified the third victim as Lu Lingzi. She was a graduate student at Boston University.


UPDATED: Federal officials are denying that a suspect is in custody in the Boston Marathon bombings.

A law enforcement official briefed on the investigation told The Associated Press on Wednesday a suspect was in custody.

But the FBI and the U.S. attorney's office in Boston dispute that.

The official who spoke to The Associated Press did so on condition of anonymity and stood by the information even after it was disputed.

The official was not authorized to divulge details of the investigation. The official had said the suspect was expected in federal court in Boston.

Reporters and police have converged at the courthouse.


EARLIER STORY: A suspect in the Boston Marathon bombings was taken into custody Wednesday in a breakthrough that came less than 48 hours after the deadly attack, a law enforcement official briefed on the investigation said Wednesday.

The official spoke shortly after several media outlets reported that a suspect had been identified from surveillance video taken at a Lord & Taylor store between the sites of the two bomb blasts, which killed three people and wounded more than 170.

The official was not authorized to divulge details of the investigation and spoke to The Associated Press on condition of anonymity. The suspect was expected at a Boston courthouse under heavy security, the official said.

A news briefing was scheduled later Wednesday.

Law enforcement agencies had earlier pleaded for the public to come forward with photos, videos or any information that might help them solve the twin bombings. Police also gathered surveillance video from businesses around the finish line.

The bombs were made from ordinary kitchen pressure cookers packed with explosives, nails and ball bearings to inflict maximum carnage, investigators and others close to the case said. But the FBI said nobody had claimed responsibility.

Investigators in white jumpsuits had fanned out across the streets, rooftops and awnings around the blast site in search of clues on Wednesday. They combed through debris amid the toppled orange sports drink dispensers, trash cans and sleeves of plastic cups strewn across the street at the marathon's finish line.

President Barack Obama branded the attack an act of terrorism. Obama plans to attend an interfaith service Thursday in the victims' honor in Boston.

Scores of victims of the Boston bombing remained in hospitals, many with grievous injuries. Doctors who treated the wounded corroborated reports that the bombs were packed with shrapnel intended to cause mayhem. In addition to the 5-year-old child, a 9-year-old girl and 10-year-old boy were among 17 victims listed in critical condition.

The trauma surgery chief at Boston Medical Center says most of the injuries his hospital treated after the marathon bombings were to the legs.

"We have a lot of lower extremity injuries, so I think the damage was low to the ground and wasn't up," Dr. Peter Burke said. "The patients who do have head injuries were blown into things or were hit by fragments that went up."

Dozens of patients have been released from hospitals around the Boston area.

At Massachusetts General Hospital, all four amputations performed there were above the knee, with no hope of saving more of the legs, said Dr. George Velmahos, chief of trauma surgery.

"It wasn't a hard decision to make," he said Tuesday. "We just completed the ugly job that the bomb did."

The bombs exploded 10 or more seconds apart, tearing off victims' limbs and spattering streets with blood. The blasts near the finish line instantly turned the festive race into a hellish scene of confusion, horror and heroics.

The blasts killed 8-year-old Martin Richard, of Boston, and 29-year-old Krystle Campbell, of Medford. The Shenyang Evening News, a state-run Chinese newspaper, identified the third victim as Lu Lingzi. She was a graduate student at Boston University.


EARLIER STORY

BOSTON — A suspect in the Boston Marathon bombings was taken into custody Wednesday in a breakthrough that came less than 48 hours after the deadly attack, a law enforcement official briefed on the investigation said Wednesday.

The official spoke shortly after several media outlets reported that a suspect had been identified from surveillance video taken at a Lord & Taylor store between the sites of the two bomb blasts, which killed three people and wounded more than 170.

The official was not authorized to divulge details of the investigation and spoke to The Associated Press on condition of anonymity. The suspect was expected at a Boston courthouse, the official said.

A news briefing was scheduled later Wednesday.

Law enforcement agencies had earlier pleaded for the public to come forward with photos, videos or any information that might help them solve the twin bombings.

Investigators circulated information about the bombs, which involved kitchen pressure cookers packed with explosives, nails and other lethal shrapnel. But the FBI said nobody had claimed responsibility.

A person close to the investigation had previously told AP the bombs consisted of explosives put in 1.6-gallon pressure cookers, one with shards of metal and ball bearings, the other with nails.

Investigators in white jumpsuits had fanned out across the streets, rooftops and awnings around the blast site in search of clues on Wednesday. They combed through debris amid the toppled orange sports drink dispensers, trash cans and sleeves of plastic cups strewn across the street at the marathon's finish line.

President Barack Obama branded the attack an act of terrorism. Obama plans to attend an interfaith service Thursday in the victims' honor in Boston.

Scores of victims of the Boston bombing remained in hospitals, many with grievous injuries. Doctors who treated the wounded corroborated reports that the bombs were packed with shrapnel intended to cause mayhem. In addition to the 5-year-old child, a 9-year-old girl and 10-year-old boy were among 17 victims listed in critical condition.

The trauma surgery chief at Boston Medical Center says most of the injuries his hospital treated after the marathon bombings were to the legs.

"We have a lot of lower extremity injuries, so I think the damage was low to the ground and wasn't up," Dr. Peter Burke said. "The patients who do have head injuries were blown into things or were hit by fragments that went up."

Dozens of patients have been released from hospitals around the Boston area.

At Massachusetts General Hospital, all four amputations performed there were above the knee, with no hope of saving more of the legs, said Dr. George Velmahos, chief of trauma surgery.

"It wasn't a hard decision to make," he said Tuesday. "We just completed the ugly job that the bomb did."

The bombs exploded 10 or more seconds apart, tearing off victims' limbs and spattering streets with blood. The blasts near the finish line instantly turned the festive race into a hellish scene of confusion, horror and heroics.

The blasts killed 8-year-old Martin Richard, of Boston, and 29-year-old Krystle Campbell, of Medford. The Shenyang Evening News, a state-run Chinese newspaper, identified the third victim as Lu Lingzi. She was a graduate student at Boston University.


EARLIER STORY

A law enforcement official briefed on the investigation says a suspect has been taken into custody in the Boston Marathon bombings.

The official spoke to The Associated Press on condition of anonymity Wednesday. The official was not authorized to divulge details of the investigation.

The official says the suspect is expected in federal court in Boston.

Law enforcement agencies had earlier pleaded for the public to come forward with photos, videos or any information that might help them solve the twin bombings that killed three people and wounded more than 170 on Monday.

Investigators circulated information about the bombs, which involved kitchen pressure cookers packed with explosives, nails and other lethal shrapnel. But the FBI said nobody had claimed responsibility.


EARLIER UPDATE

A law enforcement official reports that the Boston Marathon bomb suspect is in custody and expected in federal court.


EARLIER UPDATE

BOSTON -- A law enforcement official reports that an arrest is imminent in the Boston Marathon bombing and a suspect is to be brought to court.

Details to come.