A convicted murderer who is facing possible execution was beaten repeatedly with a coconut branch as a child or sometimes had coffee thrown in his face, family members testified in federal court Thursday.

William Sablan, 43, was found guilty in the death of a fellow inmate, Joey Estrella. In October 1999, Sablan strangled Estrella, 33, in their federal prison cell, cut his throat at least 60 times with a contraband plastic razor and removed the victim's organs.

Now a jury is trying to decide whether he should be put to death for his violence. Testimony is scheduled to continue today.

"I blame them (Sablan's parents) for William being like that," his sister, Julita Taisacan, told jurors Thursday.

Sablan's father and mother started abusing him and his 14 siblings at an early age, Taisacan said. They grew up in Saipan in the Northern Mariana Islands, a U.S. commonwealth.

The parents would wake the kids at 5 a.m. and force them to do farm work before getting ready for school.

When they got home, the children either did more chores or slept, she said.

If the children disobeyed or did something wrong, they would get beaten by their father, she said.

Sablan was beaten the most, and at the age of 12, he moved in with his brother's family, relatives said.

"It didn't stop," said Maggie Sab-lan, the defendant's half sister who took the teen into her home. "(His) father would come to the house and scream and yell at him. He would smack him or throw coffee at his face."

Despite his rough childhood, Sablan was a good man and father, family members testified.

He was close with his children and taught them the best spots to catch octopus or hunt birds in the jungle, they said.

"He is bright," Taisacan said. "He didn't have a chance because of the parents. It's too much abuse."

Family members said Sablan changed after several head injuries and after his daughter, May, died in a car accident.

David Lovejoy, a neuropsychologist, testified Thursday that Sablan suffers from traumatic brain injury, psychotic disorder and post-traumatic stress disorder and childhood abuse.

Prosecutors have argued that Sablan is too dangerous to live in prison.