The parents of a former Kaiser High School football player confronted the varsity head coach minutes after their son showed up for — but did not participate in — team picture- taking, according to testimony in the trial of one of the parents.

The Sept. 18, 2017 confrontation prompted the state Department of Education to cancel the rest of Kaiser’s football season and the coach, Arnold Martinez, to resign. It also resulted in criminal charges.

Gregory Tartamella, 42, is on trial in state court on charges of assaulting and harassing Martinez, and threatening security attendant Nick Hironaka and then-Vice Principal Kevin Dias.

Deputy Prosecutor Catherine Lowenberg played a cellphone video of the confrontation multiple times Wednesday for the jury.

Martinez pointed out to the jury the part of the video that he says shows Tartamella hit him on the arm and shoved him. Martinez suffered a bruise to his left forearm. The assault is a felony because Martinez was a educational worker. In addition to coaching, he was a teacher.

Tartamella has yet to testify. His lawyer Eric Seitz told the jury in opening statements that Tartamella was angry but “he didn’t go there looking for a fight, he didn’t go there with any intent to hit or strike anybody and that he did not strike or hit anybody.” He did not say what Tartamella was upset about.

Martinez told the jury that in 2017 Tartamella’s son was a Kaiser freshman who played on the school’s junior varsity team. He said after the boy injured his arm in an early-season game against Radford High School, he stopped attending team practices, choosing instead to sit in the bleachers.

When an assistant coach invited the boy to join the team on the field, Martinez said the boy got emotional and said his parents wouldn’t let him. Martinez said Tartamella then intervened and told the assistant coach not to talk to the boy.

Martinez said an injured player is still part of the team but a player is presumed to have quit if he misses three practices without communicating to the coaching staff.

When he saw that the boy showed up to have his picture taken with the team, Martinez invited Kaiser Athletic Director Nelson Chee to ask the boy whether or not he still wanted to be on the team.

Chee testified that when he asked the boy why he hadn’t showed up for two weeks, the boy said, “Well, I was thinking about quitting anyway.” When he asked if he was sure, Chee said the boy answered, “I think I’ll quit.”

Chee also testified that the boy was not allowed to have his picture taken because he had quit.

He said Tartamella and his wife showed up on campus 20 to 30 minutes later.

Jennifer Erb, who had two sons at Kaiser, testified that she saw Tartamella and his wife going after and verbally attacking Martinez, “like a junkyard dog.”

The Tartamellas are heard in the video challenging Martinez to fight and threatening to sue.

Erb said, “It was very obvious to me they were trying to incite an incident.”