A newborn infant girl was “spontaneously revived” almost two hours after being pronounced dead at a Toronto, Canada, hospital on Sunday, in a medical case that has doctors and police puzzled.

According to the Toronto Star, the infant’s 20-year-old mother was on her way to the hospital on foot early Sunday morning, when she unexpectedly went into labor in the middle of the street in the bitter cold.

“She wasn’t feeling well, and her and her mother were walking to the hospital,” police Constable Wendy Drummond told the paper. The young woman and her mother were walking along York Gate Blvd., a street that had been partially blocked off by snow banks, when the journey became too much for her.

The pair were less than 550 yards away from Humber River Hospital, when the young woman began going into labor on the sidewalk. Shortly after delivering the baby, paramedics arrived and transported them to the hospital. But after “extensive resuscitation efforts” to revive the baby girl, medical staff pronounced the infant dead.

About an hour and 45 minutes passed before police officers assigned to guard the infant’s body noticed something was amiss. One of the officers observed movement underneath the sheet; after finding that the infant had a pulse, they notified doctors who confirmed that the child was alive.

“There weren’t life-saving measures taken by the officers, but it’s very important the officers were there and noticed some movement,” Drummond said, adding that the child’s mother remained in the hospital and was in good condition. Drummond said the two officers who notified medical staff of the child’s pulse declined to publicly comment on it.

“Today two officers experienced something most likely never to happen again in their careers,” Drummond tweeted on police department’s Twitter page. “Truly astonished/pleased baby is doing well.”

Deputy chief Peter Sloly also expressed his joy on Twitter, writing, “A#TPS cops … saw the baby move, got a pulse + saved its life!”

In an email to the Star, hospital spokesman Gerard Power said that Humber River Hospital was reviewing the incident with the appropriate agencies but could not comment further due to privacy laws.