Arson investigators are working closely with the Aurora police Major Crimes Unit. They're treating the case like a homicide investigation, because two people died in the fire, said 7NEWS reporter Amanda Kost.

Another 25 people were injured when fire engulfed hallways at the Fitz Apartments at 1747 N. Peoria St. around 11 p.m.

Some people jumped to escape the flames.

The owner of the apartment complex said he suspects the fire was not an accident.

"We have our suspicions as to who may have caused this," the owner, who didn't want his name used, told 7NEWS reporter Lance Hernadez. "There's too many factors about it... It wasn't coincidental."

The apartment complex is located across the street from the University of Colorado's Anschutz Medical Campus and just a few yards from the still boarded up windows of an apartment where movie theater shooting suspect James Holmes once lived.

The Fitz Apartments owner said he thinks the fire was set by a copy-cat criminal, who'd heard about the booby-trap fire-bomb that police accuse Holmes of rigging in his apartment.

During the blaze, firefighters on ladder trucks rescued several people on the upper floors.

"I've got a lot of rescues going on all around this building," a fire official radioed at one point.

A woman trapped in a fourth-floor bathroom was "screaming for help," a firefighter radioed.

People described a desperate dash to escape through burning hallways.

"It was almost like staring at the gates of hell," said Steve Southard, the maintenance manager at the apartment complex.

He's still amazed he and his family survived.

"How do I get out? How do I get my kids out?" Southard asked.

Witness Tayveon Lewis told 7NEWS they helped rescue a family from the 4th floor.

"We ripped a canopy out of the ground, climbed up there," Lewis said. "Had them throw the baby out, caught the wife, the husband, had them climb down and rescued them."

The couple who died in the fire had apparently lived in the building for more than 20 years.

Authorities will not officially release the victims' names until an autopsy is conducted on Wednesday.

But neighbors told 7NEWS that Bounhieng Thammavongsa and his wife Dom never made it out of their bedroom in unit 404.

Thammavongsa was a maintenance supervisor at Aurora Hinkley High School. Dom was a stay-at-home wife.

“They were probably the finest couple I’ve known in many years,” said the owner of the apartment complex.

Thammavongsa’s brother, Kim Apaseuth, said he learned about the fire several hours after it happened.

“I came here (yesterday) to watch the Olympic games with my brother,” Apaseuth said. “I left around 4 or 5 o’clock.”

Little did Apaseuth know that that would be his last visit.

Apaseuth said Thammavongsa was planning to retire soon, in part because of health issues.

“He went to see the doctor because he has diabetes,” Apaseuth said. “He had a problem with the eye and the foot.”

Late Tuesday, Apaseuth said he was still awaiting official word on his brother and sister-in-law.

The apartment fire was a three-alarm fire, so 40 to 45 firefighters and support staff were called out to help fight the fire.

Twenty-five people were treated on scene, and 15 of them were taken to local hospitals, according to Aurora Fire Department spokesman Capt. Alan Robnett.

Southard, the maintenance manager, said he also oversees security video for the buildings.

"Last night it caught every minute of it that was going on out here. The cameras in between buildings caught it all," said Southard.

Southard said he turned that video over to Aurora arson investigators.

Investigators told Kost that they obtained security video from the apartment building and nearby businesses.

Firefighters were also inspecting the apartment building's HVAC system. The apartment did not have a sprinkler system because it was built in a time when that was not required.

More than 40 people checked into a nearby Red Cross shelter at Paris elementary school earlier Tuesday. One of two buildings evacuated during the fire reopened to residents around 7 a.m., leaving around 30 people at the shelter, a spokeswoman said.