Altoona police and fire officials investigate Tuesday after an apartment blaze in Altoona. Five people from separate units in the Altoona two-story duplex died in the fire, Blair County Coroner Patricia Ross said. Three other residents of the downstairs apartment escaped.

ALTOONA — Investigators are trying to pinpoint the cause of what’s being called the deadliest fire in the city in decades, an apartment house blaze that killed five people.

The victims of the second-floor apartment fire died of smoke inhalation, Blair County coroner Patricia Ross said. Three residents escaped from an apartment on the first floor, where smoke alarms were ringing.

Authorities were focusing the investigation on a living area toward the front of the second-floor apartment, city police Sgt. Benjamin Jones said. The man who rented the apartment, Baron Richard Snyder Sr., used that area as his bedroom, neighbors said.

Police wouldn’t say whether the fire was suspicious, but they were treating the building as a crime scene, Jones said.

The red brick home in Altoona already was enveloped in flames when firefighters arrived from a nearby station at around 6:45 a.m. Tuesday, said fire Deputy Chief Tim Hileman, a 13-year veteran.

“In my years in the Altoona Fire Department, I’ve seen few fires that have had as much ... flames and smoke,” Hileman said. “It was a definite tragedy that we hadn’t seen it in a while.”

The last time so many people died in a fire in the city was in the 1970s, when five children perished, Hileman said.

Blair’s office identified Tuesday’s victims as: Snyder, 40; his stepfather, Thomas Boyles, 57; Christopher Alvord, 23; Warren Arthur Carter Jr., 35; and Joey Allen Middaugh, 17. All lived in the second-floor apartment of the two-story duplex except Middaugh, a Huntingdon resident who was friends with Alvord.

The building passed code inspection two months ago and had smoke detectors, but it was unclear whether they were working on the second floor at the time of the fire, Hileman said.

It took about an hour for 30 firefighters to get the blaze under control on a dead-end street in a middle-class neighborhood near downtown. Some firefighters went through several breathing devices because they didn’t want to stop searching for survivors, Hileman told the Altoona Mirror newspaper.

Neighbors mingled Tuesday afternoon as children returned home from school past the cordoned-off block. Fire investigators continued to inspect the charred ruins on the second floor, including a sagging wooden porch at the front of the house.