FUQUAY-VARINA — Officials have released the names of two men who died in an early morning house fire Sunday, but investigators are still trying to determine what caused the blaze.

Leroy Dunlap, 59, and Arthur Lee Harris Jr., 46, were sleeping in the basement closest to the origin of the fire, said Fuquay-Varina police Capt. Bob Adams. Investigators have not said how the two died.

The fire at 128 Bridge St. was called in at about 7:32 a.m. The first fire units on the scene reported heavy fire in the rear of the house and attacked it with hose lines.

"Fire conditions when we got there were tremendous," said Fuquay-Varina Fire Chief Tony Mauldin.

He said crews had to beat back the fire before conditions improved enough to allow firefighters inside for search and rescue operations. When firefighters found Harris and Dunlap, they were already dead, Mauldin said.

It appears one of the tenants in the building made the original call about the fire and told rescuers there were still people inside, he said.

Six people were at home at the time of the fire. All are believed to be related, said Adams. The American Red Cross is helping the survivors.

Wake County tax records show the house is owned by Forest Newkirk Jr. and Ruby Newkirk of Raleigh. The brick house sits on a slope and is one story facing the street; a basement living area is on the back side.

Martha McKethen lives across the street from the fire. She said she heard a big boom and thought something had blown up.

“It was just chaos,” she said.

Margaret Easton also lives across the street said the smoke made it difficult to even see the burning house.

“When I opened the door, the smoke … it was so black and dark,” she said. “That’s when I ran across the street to see what was going on.”

The Wake County Fire Marshal, City-County Bureau of Identification and the federal Bureau of Alcohol, Tobacco, Firearms and Explosives are also involved in the investigation.