Unified Police Lt. Justin Hoyal says 18-year-old Talon Hamann, 20-year-old Austin S. Taylor and 18-year-old Ryan Curtz were arrested for suspicion of Workman's murder, while 18-year-old Shalynn Caro was arrested on suspicion of obstructing justice.
A neighbor who live near the Mormon chapel at 5000 South Westmoor Road discovered Workman's body and reported it to police.
Investigators say Workman's body showed signs of puncture wounds.
Family members were shocked to learn of his death.
"I really can't believe it," says his sister Jen Workman. "He and I were real close. He's a real sweet person. He would never hurt anybody."
Workman and her sisters met with ABC 4 News and they say no one was aware of who these suspects were.
"I've never seen them or heard of their names before," says Workman. "He was at that house having a barbeque and he said he'd be home by midnight. That was the last we heard from him."
His four sisters find his manner of death puzzling because of his good spirited nature.
"He was the most loving person that you'll ever meet in your life," says Tina Hale another of his sisters. "He loved everyone and everyone we know loved him."
According to Hoyal, it appears that Hamann, Taylor, and Curtz did not know Workman, but believed Workman got into an argument with one of their friends.
"Whatever that disagreement was about, it precipitated this fight," says Lt. Hoyal.
Based on their belief of the argument, Hoyal said the group went after Workman, and located him at the church where an altercation took place.
Hoyal said a witness came forward and identified the people involved in the fight.
Through interviews and witness statements, Hoyal said it was determined Hamann stabbed Workman.
"The other two (Taylor and Curtz) were punching him as Hammon was stabbing him," says Lt. Hoyal.
Hoyal said Caro drove Hamann and Taylor to the scene, witnessed the murder and then drove the suspects from the scene.
Hamann was booked into the Salt Lake County Jail for murder, a first degree felony. Taylor was booked into the Salt Lake County Jail for felony murder, a first degree felony. Curtz was expected to be booked into the Salt Lake County Jail for felony murder, a first degree felony.
Caro was booked into the Salt Lake County Jail for obstructing justice, a second degree felony.
In lieu of flowers, the Workman family asked that people make donations to the "Michael Robert Workman Estate" account set up at Mountain America Credit Union.