In addition to the murder charge, Joshua Arthur Mielke, 16, was charged as an adult with two counts of aggravated kidnapping and two counts of firing a gun causing serious injury, aggravated assault, all felonies and assault, a class A misdemeanor. If convicted, the charges will all carry gang penalty enhancements.
KSL TV doesn't typically name juveniles accused of crimes but is naming Mielke because he is charged as an adult.
All of those charged, police claim, are also gang members. Previous charged are Christian De La Rose, 17, Mateo Heriberto Martinez, 21, Alex Daniel Ruiz Martinez, 19, and a 15-year-old who has not been named.
Mielke will be held without bail, accused of killing Welday, after, police say, the accused asked the victim and his friends about being involved in rival gangs.
Police were called to the Mount Olympus trailhead in the early morning hours of Aug. 3 after two friends were with shooting victim Welday and called 9-1-1. The other two managed to escape from the attackers and call for help.
The first person attacked -- before the suspects surrounded the car where Welday was killed -- hid from the accused. He was carrying the car keys, leaving the other two unable to drive away. The remaining two locked the car doors and called 911 as the suspects surrounded the car, two on each side.
According to court documents, when the car windows were shattered, and the pair inside was attacked, one victim was hit in the head with what he believed was a hammer and fell to the ground and then rolled off the trailhead's retaining wall to the road below. He was able to run west across roads, including Interstate 215. He lost his phone and knocked on doors in a neighborhood to get help. A resident called 9-1-1.
Fourth suspected gang member charged for killing at Mount Olympus trailhead
"There is substantial evidence implicating Joshua Arthur Mielke in the homicide," charging documents state. "Location data for the defendant's cell phone shows that it was at the trailhead at the time of the offense, and moving away from the incident with co-defendants."
Police said the behavior of the accused is consistent with behaviors known by gang detectives. Police said the regular challenge individuals they believe are in rival gangs.
"Mielke has a significant delinquency history including firearm related offenses and fleeing police, making him a continuing risk to the community."
Documents also said Mielke was a fugitive from the juvenile justice system and said he had removed his ankle monitor.