Story highlights A woman has been charged with kidnapping in case

Baby found safe and in "excellent health," police say

She is in an Iowa jail on an unrelated charge

Kayden was just 5 days old when he disappeared early Thursday

A 6-day-old Wisconsin baby who vanished from a home early Thursday has been found safe at an Iowa gas station, authorities said Friday.

The U.S. attorney in Madison, Wisconsin, has filed charges of kidnapping against Kristen R. Smith, in the case of 6-day-old Kayden Powell, who was found at an Iowa gas station Friday after going missing from the child's Wisconsin home early Thursday.

Smith took Kayden Powellt from a home in Wisconsin and transported the the infant across state lines to Iowa, the federal complaint against her claims.

An officer found Kayden Powell Friday morning. The child was swaddled in blankets inside a tote bag at a West Branch, Iowa, gas station, according to Town of Beloit, Wisconsin, police Chief Steven Kopp.

"Despite frigid temperatures, Kayden was found alive, and appears to be doing very well," Kopp said. "In the words of EMS officials, he is in excellent health."

Kristen R. Smith faces kidnapping charges after baby clothes were found in her car.

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The baby was found outside the building, according to G.B. Jones, acting special agent in charge of the Milwaukee office of the FBI.

"We're all very, very fortunate that this baby is alive," Jones said.

Smith was jailed Thursday in Iowa on an unrelated fraud warrant out of Texas after police investigating Kayden's disappearance contacted her on her cell phone and asked her to report to a nearby police station, authorities said.

When police searched her car, they found baby clothes, but no sign of the infant, Kopp said Thursday.

Kayden's mother is 18-year-old Brianna Marshall.

Smith reportedly said at the home that she was Marshall's half-sister and that she, Marshall and the baby's father would be moving to Colorado, according to CNN affiliate WKOW

Authorities searched feverishly along the travel route back to Colorado after discovering the baby was missing, Jones said.

"We did have troopers, deputy sheriffs and police officers out all night checking every conceivable place along that route," Jones said.