HUNTINGTON, W.Va. (AP) — Investigators tunneled through debris Monday, searching for more victims and clues to the cause of a fire at a five-story apartment building that killed at least eight people, including a 7-year-old boy.

Huntington Fire Chief Greg Fuller said the building’s roof and part of that floor had collapsed, hampering search efforts.

“It’s very dangerous, that’s why we have to move slowly and methodically,” Fuller said at an afternoon news conference.

Two people were missing and eight were unaccounted for, Fuller said.

There was no sprinkler system in the building. While sprinklers are not required under state law, smoke alarms are, and investigators were checking whether the circa-1924 building was in compliance. Several smoke alarms were found, Fuller said.

“I think they would have made a huge difference,” Fuller said.

Alex Vence, who manages the building for owner Woodlark Enterprises Inc., said there were smoke detectors in every apartment but tenants were responsible for reporting dead batteries or other problems. He also said fire officials had inspected the building recently and found no violations.

“We make sure the smoke detectors are in the rooms but it’s not up to us to make sure they’re working,” Vence said Monday.

“We’ve never had any kind of violations. We’ve made every effort to make it safe for tenants.”

Woodlark Enterprises, based in White Plains, N.Y., did not return a telephone message.

Roger Smith, the building’s former owner, said he was devastated by the fire.

“It’s just unbelievable this could happen. This building was built like a fortress,” Smith said.

The fire, the worst in Huntington in nearly 50 years, was reported around 11 p.m. Saturday. Officials said it began in a second-floor unit, shooting flames and smoke up utility access channels to the upper floors. City Fire Marshal David Bias said it could take days to identify the cause.

Fuller said firefighters found three bodies Saturday and four more Sunday, all on the top story. Another person died Monday at Cabell Huntington Hospital, Huntington police said.

Two other people remained in serious condition Monday at the hospital and a third was released, hospital spokeswoman Kathy Cosco said.

Fire officials identified seven victims: Mary Biss, 68; Beatrice Yancy, no age; Seth Justas, 7, and his mother, Ann Saleh, no age; and siblings Ben A. Lucas, 19, Angel R. Lucas, 17, and Quentin Lucas, 14. The name of the eighth victim, a male, has not been released.

Twenty-four people were rescued, Fuller said.

The building housed city residents as wells as students from Marshall University.

“There’s nothing more devastating. It’s just an unbelievable experience,” Gov. Joe Manchin said.

“West Virginia’s not that large. We are family and it affects every one of us,” he said.

Marshall said one victim was a student but it declined to identify them. Seven students were relocated to the university’s residence halls and others were staying with friends or family. The American Red Cross said it was helping 26 households affected by the fire.

“This is a sad time for both Huntington and Marshall University,” Marshall President Stephen J. Kopp said. “We want to do everything we can to help any Marshall student whose life has been disrupted by this destructive event.”

An apartment building next door suffered smoke and water damage. Drew Hetzer, a resident of that building, said he was told that he could return in a week.

“I feel safe. I feel like they’ll get everything taken care of,” Hetzer said Monday.

The burned building is located on one of Huntington’s busiest thoroughfares. Officials said it would be several days before the street would be reopened for traffic.