The chance of the teen’s rehabilitation is minimal, prosecutors said in court documents.
League officials say they hadn’t had any problems with the teenager prior to this incident.
Funeral services are being held Wednesday in Salt Lake City for Portillo, who leaves behind three daughters and four grandchildren.
A wake is scheduled to run from 1 to 7 p.m., followed by a religious service. Both are open to the public.
After the funeral, Portillo’s remains will be returned to his hometown of Guadalajara, Mexico. He moved to Utah from there 17 years ago.
Family members said Portillo loved soccer, and had been working as a referee in different leagues for eight years. His oldest daughter, Johana Portillo, said he had been attacked before by players, even having his legs and ribs broken. Though his daughters begged him to quit, he said he couldn’t give up his passion.
Portillo was a longtime referee, be he was not licensed by the Utah Soccer Referee Committee.
The incident occurred in a game held by La Liga Continental de Futbol, an unaffiliated soccer league created in 2009. The league holds games for children ages 4 to 17 each Saturday at a junior high school field in Taylorsville.
The league president, Mario Vasquez, said earlier this week that the league will hold an adult, co-ed soccer tournament in Portillo’s honor May 25-26. The funds will go to his family.