PARIS (AP) — French firefighters in the northern city Lille said Sunday they had found a body under the rubble of a four-story building that collapsed a day earlier.

Authorities said that the quick thinking of a resident who noticed cracks in the building and prompted an evacuation before Saturday's collapse saved many lives.

Emergency workers on Sunday morning wrapped up the emergency rescue operation that was aimed at finding survivors or people caught in the debris. One person was rescued on Saturday with light injuries.

Head of rescue operations Stephane Beauventre told French media that the recovered body is likely to be that of a 45-year-old doctor who had been given an apartment in the building for the weekend.

Beauventre said the doctor had been missing since Saturday.

French media named the resident who sounded the alarm as Thibault Lemay, a 22-year-old student and tenant who came back home at 3 a.m. after a night out and noticed a gaping crack and a warped wall.

Lemay told France Bleu Nord radio that he was returning to “see my two roommates.”

“We realized that the building had moved because we could no longer open the door at the top and we heard rubble falling,” he said. “Very quickly we took the decision to notify the emergency services.”

The fire service responded and created a cordon around the “zone of peril” in the building, divided into commercial and residential parts.

Lille Mayor Martine Aubry said that the man’s actions saved lives.