Autopsies scheduled for Monday on six people — including four children — found dead at a Yuma home were expected to shed more light on the henious crime that has rattled this small town in southwest Arizona.

Authorities released little new information on Sunday, other than to confirm that the victims included a mother, her four children and the mother's new boyfriend.

"We're considering all options and all potential motives," Police Chief William Robinson (search) said during a news conference Sunday at the police station here.

Officers responding to a call of shots fired in a residential neighborhood late Friday found a man with a gunshot wound in the home's backyard. The man, identified as Luis Rios, 35, died later at a hospital.

Police surrounded the home and evacuated the immediate neighbors. Once inside, police found the other victims. Police wouldn't say where the victims were in the home.

A cause of death won't be released until autopsies results come back, said Officer Clint Norred, a spokesman for the Yuma Police Department (search).

Police were looking for a man seen running from the scene shortly after the shots were fired. The man was described as Hispanic, in his late 20s or early 30s with stocky build and buzz-cut hair.

Besides Rios, police identified the other victims as: Adrienne Heredia, 30; Danny Heredia III, 6; and Inez Newman, 9. The names of two other victims, both 13-year-old boys, were being withheld. Robinson said Heredia was the mother of all the children.

He said Rios was Heredia's boyfriend.

The couple had been together for about 10 months, said Theresa Guerraro, a friend of Adrienne Heredia who was at the police station Sunday.

Heredia's friends said she had a very good relationship with Rios.

"She was happy for the first time in her life," said Kisty Guerraro, another friend. "He supported her in everything she did."

Theresa Guerraro said she had no idea who the suspect is.

"I know he doesn't have a heart — to kill kids," she said.

William Anderson, a neighbor of the family, said he's known Heredia's brothers for years, and they are a good family. Heredia had not lived in the neighborhood for very long, he said.

Anderson said the fact that most of the victims were children was especially difficult.

"I've got a 14-year-old myself. It hit my heart," he said Sunday. "I was sad even before I knew who she was."