EL PASO, Texas -- Jurors deciding whether Fabian Hernandez will face the death penalty or a life prison term for double murder stayed late Friday to hear testimony from witnesses called in his defense.

An expert witness showed the jury a family tree indicating widespread alcohol abuse, physical abuse and domestic violence in Hernandez's background. He said that background has lasting effects, increasing the likelihood of relationship problems and violent tendencies. Based on his history, he called Hernandez a "damaged" human being.

Hernandez's mother also took the stand, confirming accounts of abuse in the family and alcoholism.

The jury also heard testimony about Fabian and Renee's rocky marriage that involved alcohol abuse and infidelity.

Hernandez was found guilty of two counts of capital murder for the shooting death of his wife Renee Hernandez and her boyfriend Arturo Fonseca.