I was frustrated, hit the ref and caused his death. – Jose Domingo Teran

SALT LAKE CITY — A 17-year-old charged with causing the death of a referee who was officiating his soccer match pleaded guilty Monday to a charge of homicide by assault.

Jose Domingo Teran was then sentenced to serve time in a juvenile prison until he turns 21 the maximum sentence in the juvenile system. Third District Juvenile Judge Kim Hornak also ordered that a picture of the victim be posted in Teran's cell and that he write weekly letters to the victim's daughters.

Prosecutors had filed a motion to have Teran certified to stand trial as an adult, but withdrew that motion during a hearing in juvenile court in exchange for the teen admitting to the third-degree felony. Hornak clarified through a series of questions that Teran understood his rights before accepting the admission.

"Are you admitting to this charge because it's true?" the judge asked.

"Yes," Teran replied, later explaining the crime in a brief sentence: "I was frustrated, hit the ref and caused his death."

Teran punched Ricardo Portillo, 46, after the referee in the April 27 youth soccer match called a foul on Teran. After Portillo issued him a yellow card, Teran responded by punching Portillo "in the rear jaw area with a closed fist," charging documents state.

Doctors at Intermountain Medical Center later told investigators that Portillo suffered a traumatic brain injury. He remained in a coma for a week before he died.

Two of the victim's three daughters spoke to Teran and made emotional statements. "I hope you learn your lesson," one of them told him.

Teran apologized to the victim's family. "I'm sorry I acted impulsively and childish and I've learned a lesson," he said.

Teran's mother also addressed Portillo's family and apologized for the actions of her son.

The plea deal was unexpected. On Friday, attorneys announced that they had reached an agreement that there was probable cause to show Teran had punched Portillo and a hearing where the evidence would have been presented against him was canceled. The hearing on Monday was initially to determine if Teran should be prosecuted as an adult.