Riverton, Wyoming - A parks employee in a central Wyoming city who said he was incensed by homeless people drinking in parks slipped into a detox centre over the weekend and shot two men in the head as they were lying in their beds, killing one and critically wounding the other, authorities charge.A judge on Monday ordered Roy Clyde, 32, of Riverton, held without bond. Clyde is charged with one count of first-degree murder and one count of attempted first-degree murder. A preliminary hearing was set for July 29.Riverton police Captain Eric Murphy said on Monday that Clyde is a 13-year employee of the City of Riverton. Murphy said Clyde called police after the shooting at the Centre of Hope facility and reported it. Police arrested him nearby.Clyde told investigators that he targeted the detox facility because he was tired of cleaning up after homeless people, Murphy said. "And basically he was angry at that, and that's what precipitated him to go and do this violent act," Murphy said.Park rangersDespite Roy Clyde's reported complaint, there was no immediate indication that anyone inside the Centre of Hope facility — including the victims — was homeless at the time of Saturday's attack. Moreover, police say the centre caters to all segments of the population with addiction problems.According to a police statement filed in court Monday, Clyde told investigators he had long been considering killing people he referred to as "park rangers". In Riverton, the term "park rangers" refers to homeless alcoholics — most of them American Indians. Many come to the city from the surrounding Wind River Indian Reservation, where alcohol is illegal, and drink in the parks.The reservation is home to both the Northern Arapaho and Eastern Shoshone tribes. A spokesman for the Northern Arapaho Tribe said Monday that both victims in the shooting, whom authorities have not yet publicly identified, were Northern Arapaho.Police Det. Scott Peters filed a statement in Fremont County Circuit Court on Monday that said that Clyde stated his decision was not race-based.Addiction problems"He specifically indicated that if he had encountered white people meeting his criteria, he would have killed them as well," Peters wrote.Fremont County Attorney Patrick J LeBrun said Clyde didn't yet have an attorney.According to Murphy, Clyde walked through the back door of the Centre of Hope, passed two staff members and went to an area for clients, where he shot the men. As he walked back out, he set down a handgun and was arrested soon thereafter.Some staff members and clients of the detox centre locked themselves in a bathroom when the shooting started, Murphy said.The centre, run by Volunteers of America, caters to anyone with addiction problems.A telephone call to the centre went unanswered on Monday.