HOOVER, Ala. (AP) — Investigators said Thursday a motel fire that killed four Mississippi college students, who made frantic phone calls while trapped inside, likely was caused by incense that a maintenance man left burning in another room.

No charges will be filed in the blaze itself, but the maintenance worker was taken into custody by immigration officials for overstaying a work permit by more than two years, said Police Chief Nick Derzis.

Officials said he could be deported to his native India.

Four freshmen from the Mississippi University for Women died in the blaze at a Days Inn in Hoover on Saturday night. The four, who were in town to shop, were upstairs from a ground-floor room occupied by motel maintenance man Dhirajlal Bhagat, 55.

Authorities said Bhagat who told investigators he lit incense in the cluttered room where he lived and departed for about 30 minutes, only to find his room ablaze when he returned. A man in a room beside Bhagat’s escaped.

Bhagat twice tried to use small extinguishers to douse the flames but failed. Fire quickly engulfed the wood-frame structure, which was built in the 1960s and lacked a sprinkler system.

“A sprinkler would have changed everything,” said Jim Cavanaugh, a supervisory agent with the Bureau of Alcohol, Tobacco, Firearms and Explosives.

Moments after the flames erupted, one of the victims called 911 from the motel and told a dispatcher, “‘There’s fire completely in front of our room,”’ Cavanaugh said.

As firefighters arrived and began spraying the motel with a hose, one of the women told a relative by telephone they could hear water and “the roof was falling in on them,” Cavanaugh said.

The intense heat from a wall of flame prevented the women from escaping the room or firefighters from reaching them, said Ed Paulk, Alabama’s state fire marshal. A rescue was complicated by the fact the nearest fire hydrant was down a steep hill from the motel.

The fire killed 18-year-old cousins Alondan “Angel” Turner and Catherine Ann Muse of Cordova; Jamelia Brown, 18, of Grenada, Miss.; and Jaslynn McGee, 19, or Corinth, Miss.

Brown and McGee were studying to become nurses. Muse was majoring in theater, and Turner was studying accounting and worked in an on-campus child care center.

An autopsy determined the victims died of smoke inhalation. All four bodies were found in the bathroom, furthest away from the door.

Hundreds of people attended a candlelight vigil for the victims at the college in Columbus, Miss., on Wednesday night.