A gunman shot a man and held several people hostage for about nine hours Saturday before forcing a woman and her four children into a car and fleeing, police said.

Elkhart police who issued an Amber Alert said the children and their mother were believed to be in extreme danger. The oldest child has severe asthma and needs to use a ventilator every few hours but that device was not taken, police said in a statement released Saturday night.

Police were looking for Jerry D. White, 30, who was believed to have abducted 31-year-old Kimberly N. Walker and the children after the shooting in the northern Indiana city about 15 miles west of South Bend that left a man in critical condition.

The abducted children — two boys and two girls — were identified as Jaylan Walker, 9; Justin Walker, 8; Kyara Walker, 6; and 16-month-old Kayla Walker.

Police said White may be driving either a 2000 red four-door Dodge Intrepid or a 1993 beige two-door Saturn. He was believed to be headed to the Chicago area, the statement said.

Chicago police and the FBI were assisting in the investigation. Elkhart police did not return several messages left Saturday by The Associated Press.

Elkhart police were dispatched to a home on the city's south side about 11:30 a.m. Saturday when a woman called and said her boyfriend had been shot. Officers were told the man had been shot about 1 a.m. but that the suspect had held several people captive at gunpoint and refused to allow anyone to call for help for the wounded man.

The woman called police shortly after the suspect, identified as White, forced Walker and her four children into a vehicle and fled.

The wounded man, whose identity was not released, was hospitalized in critical condition with life-threatening injuries, police said.

Neighbors told the city's daily newspaper, The Truth, that the woman moved with her children into the neighborhood around December. Neighbor Nancy Campiti said the family kept to themselves.

"I just hope they're OK," Campiti told the newspaper.