OAKLAND -- By age 12, David Mills was forced by his mother to sell drugs on the streets of East Oakland, beginning a shocking and troubling family rite of passage that was quickly followed by his younger brother and sister, family members testified in court Monday.

Proceeds from those drug sales were used to keep a roof over the family's head and to feed Mills' mother's growing drug-selling enterprise, and Mills watched as a constant river of drug users and sellers congregated at his home, the family members said.

"I used to pray and ask God to look after those kids because they didn't have the support of their mother," said Verlenia Murphy, Mills' cousin. "She put those kids through a lot."

Murphy, along with Mills' father and younger brother, testified Monday as defense attorneys for the convicted triple murderer and animal abuser attempted to convince a jury to send their client to prison for life instead of death row.

Mills, 37, faces the death penalty after the jury found him guilty last month of murdering James Martin, 28, Dale Griffin, 36 and Rebecca Martinez, 22, in 2005 as the three sat in a car in front of Mills' father's house. Mills was also found guilty of attempted murder for shooting another person in the car, Elizabeth Martinez, and two counts of animal cruelty for killing a dog and wounding a second one during the shooting.

Mills' attorney, William Linehan, has told the jury that Mills' troubled life should not

Mills' family members testifying for the defense in the penalty phase of the trial told stories about Mills' childhood, which his attorney described as chaotic and beyond dysfunctional.

Mills barely attended school, learning instead on the streets of East Oakland, which his self-described schizophrenic and alcoholic father called "Vietnam."

"It was dangerous, very dangerous, a war zone, people getting shot," said Mills' father, Duthal Barnes Jr. "Out of every four houses, one of them had something to do with drugs."

Barnes said Mills was born as a result of a relationship he had with Mills' mother, Rosie Murphy, whom he married about a year after his son's birth. But the marriage was based on physical attraction, Barnes said, adding, "love did not enter our lives."

When Mills was about a year old, Barnes said, Rosie Murphy said she no longer wanted to care for her child and sent Mills to stay with Barnes, despite his struggles with alcohol and mental illness.

Barnes said he tried his best to care for his son but when stress levels reached a certain point, his schizophrenia would take over, resulting in him being sent to a mental hospital. Barnes estimated that he had been in and out of mental hospitals at least four times during Mills' childhood.

One time, Barnes recalled, he was arrested by police after he walked to an elementary school and began shouting at children that they had to attend class.

"That was during a time when I was acting bizarre," Barnes said. "In my mind I thought school children had to go to school and I thought I was an authoritarian. I said these kids need to go to school."

When Barnes was sent to a hospital, Mills went to live with his mother in an apartment relatives described as a drug den. By age 10, Mills ran away from his father to live with his mother, in part, his brother said, because his mother didn't care what her children did as long as they sold drugs for her.

"That's all I seen, was drug transactions," said Mills' brother, Duthal Barnes III. "(My mom's) children didn't go to school and graduate, we all went to the penitentiary."

Mills' mother is expected to testify Tuesday.