The 79-year-old is representing himself. He faces a possible death penalty in the killings of four Northern California women in the 1970's and 90's.
On Monday, prosecutors used a two-minute timer to demonstrate how long it took each victim to die of strangulation.
During Naso's closing arguments, the judge called a recess twice to reprimand him for telling stories that were not in evidence.
He told the jury, "I've made a lot of mistakes. The mistakes are what got me to where I am today. It's never too late to make amends."
Naso is asking for life in prison.