DENVER – A fifth-grade teacher of Aurora theater shooter James Holmes described him as a pleasant, productive student, providing an early glimpse of how defense attorneys will try to save his life.

Paul Karrer gave videotaped testimony Monday because he is unavailable to take the stand during the sentencing phase of Holmes’ trial, which begins Wednesday and could last a month. The video will be played for jurors later.

A jury last week quickly convicted Holmes of killing 12 people and injuring 70 more during a crowded midnight movie premiere, rejecting defense arguments that he was insane and suffering delusions that drove him to the July 20, 2012, attack. The trial now enters a new phase as the jury decides whether Holmes should die for his crimes.

Karrer’s testimony signaled a defense strategy that will try to humanize Holmes and offer a sympathetic portrayal of his childhood in California. Holmes was “a really bright kid, he was the kind of kid that makes teaching very rewarding, makes you want to keep on doing what you do,” said Karrer, repeatedly referring to Holmes as “Jimmy.” He said he still cares about Holmes.

“He was a smiler,” Karrer said. “The kids liked him. There was no dark side.”

Defense attorneys will likely call others who knew Holmes throughout his life, including neighbors and possibly his parents, who attended every day of his 11-week trial.

Prosecutors, who are seeking the death penalty, may counter with even more heartbreaking accounts from victims, ranging from those Holmes maimed to the father of the youngest to die in the shooting, a 6-year-old girl. The only other option for jurors is to sentence Holmes to life without parole.