Police were searching for a man seen running from a home where six people, including four children, were killed in western Arizona (search).

Authorities released little new information on the case Sunday other than to confirm that the victims included a mother and her four children, ages 6 to 13.

"We're considering all options and all potential motives," Police Chief William Robinson said at a news conference.

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 Sunday as Luis Rios (search), 35, died later at a hospital.

Police surrounded the home and evacuated the immediate neighbors. Once inside, officers found the other victims.

Police said a man was seen running from the scene and had not been apprehended.

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

Besides Rios, police identified three of the other victims: 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. Rios was Heredia's boyfriend, police said.

The couple had been together for about 10 months and had a good relationship, said Heredia's friend, Theresa Guerraro.

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

William Anderson, a neighbor of the family, said Heredia had not lived in the neighborhood long. He 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. "I was sad even before I knew who she was."