STARKVILLE (AP) — Fire tore through an apartment early Monday, killing six children and three adults, officials said.

The blaze was reported around 4 a.m., and firefighters worked into the afternoon, shoveling piles of burned debris from the second floor of a two-story red brick apartment building in the Academy Crossing complex.

“I opened my door and all I saw was flames coming out of the front of the apartment and the glass just blew and made a sound like a bomb,” said Ramona Doss, who lives across the parking lot in a separate building. “It’s a tragedy in Academy Crossing.”

The children killed were between 4 months and 6 years old and the adults were a 25-year-old woman and two 19-year-old women, said County Coroner Michael Hunt, who did not know how they were related.

All the victims were in the same apartment and Fire Chief Rodger Mann said investigators do not yet know what caused the blaze. He said a private company recently inspected the complex and found no problems.

“A fire investigation is like a puzzle,” he said. “We’ve got to get enough pieces of the puzzle to get a picture of what happened.”

Mildred Rollins, who owns the complex, said she had no comment on the fire and referred questions to the apartment’s insurance agent, Dale Stafford of State Farm Insurance Co., who said it was too early to comment.

Several neighbors told The Associated Press the complex had electrical and other problems, but Stafford said no electrical problems had been reported to the maintenance department.

Authorities did not release the identities of the victims, and Mann said he believed they included a woman who lived in the apartment and people who were visiting her. Only three of eight apartments in the building were occupied.

Doss said the tenant would often bring her plates of home-cooked food, and the woman’s children called her “Grandma” even though they are not related.

“Those babies just had Christmas,” Doss said. “They used to say ‘Grandma, you got any more candy?’ I’ll never hear that from them again.”

Mann said it was the worst fire in recent memory in Starkville, a city of about 24,000 full-time residents that is also home to Mississippi State University, the state’s largest school. The city is about 115 miles from Jackson, Birmingham, Ala., and Memphis, Tenn.