CHEYENNE, Wyo. (AP) Three Cheyenne men will face federal charges alleging they conspired to provide the heroin and cocaine that led to the death of a Wyoming bull rider this month, a federal magistrate ruled Tuesday.

Kyle Walla, 20, Joel D. Murdoch, 22, Rhett T. Epler 26, of Cheyenne are charged with conspiracy to distribute drugs leading to the Dec. 2 death of 21-year-old Bryan Guthrie of Cheyenne. He had been a professional bull rider.

U.S. Magistrate Judge William C. Beaman on Tuesday ruled that federal prosecutors presented enough evidence to require all three defendants to answer the charge in U.S. District Court.

A fourth defendant, Christopher Charles Tyson, 35, was arrested Tuesday in Denver. All four remain in custody.

David Stevens, an officer with a U.S. Drug Enforcement Administration task force in Cheyenne, testified Tuesday that a confidential source told him that Walla, Murdoch and Tyson had traveled to Denver on Dec. 1 in Walla's car to buy heroin. They had about $150 including $30 or $40 that Guthrie had chipped in.

Once they arrived back in Cheyenne, they dropped Tyson off at a trailer park and then Walla and Murdoch proceeded to Guthrie's house. The three all used heroin together with the confidential source. The confidential source found Guthrie dead in his bedroom the next morning.

Guthrie was ranked as high as third in bull riding in January in the Professional Rodeo Cowboys Association. He was knocked out of competition with a leg injury in March.

Stevens said he been investigating allegations that Tyson was dealing heroin around Cheyenne for several months. Stevens confidential sources told him Tyson and Epler were selling "black tar" heroin around Cheyenne.

Stevens said the Laramie County Coroner's Office hasn't concluded tests on what killed Guthrie. However, Stevens said the condition of Guthrie's body was consistent with a drug overdose.

Lawyer Thomas Fleener, representing Murdoch, said all the people at Guthrie's house the night he died were close friends. He said there was no evidence that Murdoch was selling drugs.

Lawyer Tom Lee, representing Epler, emphasized that his client wasn't present the night Guthrie died. He said the only evidence of a conspiracy was that Murdoch, Walla, Guthrie and the confidential source conspired with each other to obtain and use heroin.

Lawyer Thomas Jubin represents Walla. Jubin said Guthrie's death was unfortunate, but said there was no evidence that Walla was involved "in any kind of trafficking conspiracy causing Mr. Guthrie's death."

Robert Murray, prosecutor with the U.S. Attorney's Office, told the judge that the conspiracy charge was appropriate. He said Tyson relied on the younger men to provide him with transportation, cash and cellular phones to line up drug deals in Denver that allowed him to distribute heroin and cocaine in Cheyenne.

Beaman said the government's evidence clearly supported the conspiracy charges. He said the evidence showed that Tyson was the hub of the drug distribution while the other three defendants served as "spokes of that wheel" to help him move drugs.

Beaman also denied requests from lawyers representing Epler and Walla to release them to treatment programs pending their federal prosecution. Murdoch was ineligible for release because of a pending state probation violation charge, lawyers said.

Beaman said he would consider releasing the men on bond once they've had a period of time without drugs. He said "all three are either current or recent users of a hideous drug heroin."