He faces up to 30 years in prison when he is sentenced Sept. 8 by Judge Katie Bernards-Goodman.
Angilau shot Fakatoufifita multiple times outside a convenience store at 1680 S. Redwood Road about 1:15 a.m. on April 13.
According to charges, Angilau killed Fakatoufifita because they were members of rival gangs.
After the shooting, Angilau fled and discarded a hooded sweatshirt and a firearm in the nearby Jordan River surplus canal, according to charges. Both items were later recovered by police and the firearm was matched to the bullets that killed Fakatoufifita, according to charges.
Fakatoufifita was planning to get married in May 2013 to Morgan Maree Janet Holst, who changed her story again and again to police investigating the murder.
Holst last year pleaded guilty to second-degree felony obstruction of justice, as well as first-degree felony aggravated robbery and second-degree felony burglary in an unrelated case. In exchange for the pleas, prosecutors dismissed aggravated kidnapping and retail theft charges.
In May, Holst, 19, was sentenced to six years probation and one year in jail, with credit for time served.
Angilau's older brother, 25-year-old Siale Angilau, was fatally shot by a deputy U.S. marshal on April 21, the first day of Angilau's gang-related trial in Salt Lake City's federal courthouse.
Angilau had been identified by federal prosecutors as a member of the Tongan Crip Gang and was indicted on racketeering charges in May 2010.
The marshal, whom the FBI has not identified, shot Angilau four times when Angilau allegedly grabbed a pen and rushed toward a witness who was testifying against him.
Last week, the U.S. Department of Justice found that the marshal was justified in the fatal shooting.