A 22-year-old autistic man was killed Thursday night in a Kalihi Valley fire that destroyed a multilevel house.

Three men who were separately driving by stopped when they saw the flames at about 6:35 p.m. The victim’s 11-year-old sister was outside saying, "My brother’s inside! He’s autistic," said James Ubias, 24, adding that flames were coming from the bottom level at the front of the house.

"We heard him coughing," he recalled. "We heard him screaming. Then he stopped."

Firefighters discovered the man’s body 10 to 20 feet inside the door of a second-floor room.

The house, built on a hillside at 1915 Kalihi St., is considered a total loss, said fire Capt. Terry Seelig.

Investigators will try to determine the cause today.

Forty firefighters responded to the 6:35 p.m. alarm fire, and the first company arrived in four minutes. The fire was under control at 7:12 p.m.

Residents say four families live in four sections of the house.

The victim’s 49-year-old mother and sister wept on the sidewalk across the street from the smoldering house Thursday night.

Jack Roberts, who also went up to help, said, "We heard the guy coughing. We tried to kick in the door."

But the fast-moving fire generated too much smoke, Ubias said.

Giana and Justin Santana had just gotten home from visiting a relative at the hospital with their three young children when the eldest, 7, cried at the sight of their burning home.

Three children of a third family, ages 13, 8 and 4, got out safely along with four other family members who were visiting. Neither parent of the three kids was home.

Love Enlet said the family was watching TV when her 14-year-old brother in another room smelled smoke and told them to get out.

She said the victim was handicapped and "doesn’t listen when his sister called him."