WEST BRANCH, Iowa — Manager Jay Patel was working in the BP station around 10 a.m. Friday when West Branch Police Chief Mike Horihan walked in and asked if he had heard about the missing baby. Patel gave Horihan permission to look around outside the store.

As Horihan walked around the north side of the building, he heard crying and lifted the lid of a plastic box on the ground, Patel said.

Within minutes, Horihan had called the FBI and an ambulance service, which picked up 6-day-old Kayden Powell, Patel said. The baby was swaddled in a blanket but healthy and responsive.

The BP station where Kayden was found is on the same street as another gas station where West Branch police arrested Kristen Rose Smith, 31, of Denver, Colo., on Thursday. She was being held on a warrant out of Texas in regard to tampering with government records and fraud.

On Friday, John Vaudreuil, the U.S. Attorney for the Western District of Wisconsin, in Madison, charged Smith with kidnapping. If convicted of the federal kidnapping charge, Smith will face a maximum penalty of life in federal prison.

Smith told authorities she had put the baby behind the gas station, according to the complaint filed by the U.S. Attorney.

The infant was reunited with his parents Friday afternoon who returned to their home in Beloit, Wis.

Kayden was reported missing around 4:30 a.m. Thursday from his home in  Beloit. The initial investigation indicated the baby’s mother, Brianna Marshall, woke up and found the baby missing. According to an affidavit accompanying the kidnapping charge, Smith is the mother’s half-sister and had visited the family in Wisconsin.

FBI spokeswoman Sandra Breault in Omaha, Neb., would not comment on where the baby was during the 24-plus hours before he was found.

The low temperature Friday morning in Iowa City was 11 degrees below zero, with a wind chill of 23 degrees below zero, according to the National Weather Service in the Quad-Cities. The wind chill was 30 degrees below zero just before 8 a.m. Thursday.

“I think miracle comes into play in this one if it was outside for 29 hours,” said Dr. Joshua Stilley, an emergency medicine physician at University Hospitals, Iowa City.

A baby without clothing would die within minutes in that kind of weather, Stilley said. The blankets must have wrapped Kayden up well enough to contain the heat, and the container and the positioning next to the gas station may have helped block the wind, he said.

Patel had been working at the store all morning and hadn’t seen anything suspicious, he told The Gazette.

“I see people come and go, but I didn’t see anything” related to the baby, he said.

Finding the child alive is close to a miracle, Patel said.

“It’s exciting that the baby was still alive in this cold weather,” he said.

Milwaukee FBI Acting Special Agent-In-Charge G.B. Jones said the effort now is “clearly focused on reuniting mother and child and the rest of the family members with the child.”

(Gazette reporters Erin Jordan and Gregg Hennigan contributed to this story, as did the Associated Press.)