Sowell, 51, was convicted in July of aggravated murder, abusing a corpse and tampering with evidence in the deaths of 11 women whose bodies were found at his home in 2009. He was also convicted of trying to kill three other people who survived, The (Cleveland) Plain Dealer reported.
Relatives of several victims were in court to hear attorney John Parker help Sowell during the second week of the mitigation phase in his capital murder trial.
Sowell described his life, talking about his time already spent in prison and the jobs he worked after his release. He alleged he'd been abused as a child, beaten with canes and whipped, The Plain Dealer reported.
Although Sowell didn't outright admit killing all 11 women, he apologized.
"The only thing I want to say is I'm sorry. This is not typical of me," Sowell said. "I know it's not enough, but that's all I can give you."
The apology didn't sit well with some of the victims' relatives.
"It was rehearsed and weak," said Donnita Carmichael, daughter of victim Tonia Carmichael.
"That sorry statement was not good enough for me but that is all we are going to get," said Lynnette Taylor, sister of victim Amelda Hunter.
The defense closed its case Monday. The prosecution's rebuttal witnesses will take the stand this week, The Plain Dealer said.
Kim Kardashian, Kanye West reportedly set wedding date
NBC reportedly holds celebs hostage to Jimmy Fallon's show