CORTEZ, Colo. -- An 18-year-old with a juvenile arrest record and a history of violent behavior was being held in New Mexico in the death of an openly gay, half-Navajo teenager from Cortez.

Shaun Murphy of Farmington, N.M., was arrested Thursday on a Colorado murder warrant. He was held at the San Juan County Jail in Aztec, N.M., until extradition papers could be completed.

Murphy is accused in the murder of Fred C. Martinez Jr., 16, of Cortez.

Martinez wore makeup, curled his hair and told his teachers he wanted a sex change operation. Several friends said that he was teased for his effeminate behavior, but that Martinez would laugh and brush off the taunts.

Martinez's mother, Pauline Mitchell, last saw him on June 16 when he left home to attend the annual rodeo and carnival in Cortez. His body was found five days later. He had been severely beaten. Authorities said that they believe Martinez was killed some time after he left a rodeo carnival and, later, a party attended by a few dozen young people.

Montezuma County Sheriff Joey Chavez said Thursday that he won't release any more details surrounding Murphy's arrest for several days because the investigation was still at a "very critical" stage.

Criminal courts in Montezuma and San Juan, N.M., counties have sealed records connected to the case. Chavez said only that Murphy had once lived in Montezuma County and recently moved to New Mexico. He wouldn't comment on a motive.

"At this time I can't say 100 percent that it was a hate crime, and I can't say 100 percent that it wasn't," Chavez said.