Melissa Hanson, a 19-year-old found dead in her bedroom closet June 10, was asphyxiated, South Lake Tahoe Police Detective Martin Hewlett said.
The cause of death is still under investigation because police are awaiting results of toxicology tests they expect in the next two or three weeks, Hewlett said.
Charles "Chad" Newport pleaded not guilty June 14 to first-degree murder charges in connection with the death of Hanson, known to many as Melissa Monoogan.
If Newport is convicted of murder he could be sentenced to 25 years to life in prison. His preliminary hearing is scheduled for Thursday at 8 a.m. in El Dorado County Superior Court.
El Dorado County Sheriff's Department took Newport into custody for violating probation and because they found "a note that expressed his involvement in Hanson's death."
Hanson's body was found by her mother around 6:30 a.m. at the 800 block of Clement Street.
After hearing noise coming from the room, her mother knocked on Hanson's bedroom door around 6 a.m. and a received a response from an unknown male. Minutes later she entered the room and found her daughter's body inside the bedroom closet, police said.
Newport, 19, avoided police before he was found June 12 near the parking lot of Angora Lake Trailhead. Deputies reported that he was "under the influence" of a drug and arrested him for violating probation.
In August, Newport was sentenced to three years of probation and seven months in the El Dorado County Jail for his involvement in a home invasion Jan. 31, 1999 at the 3100 block of Oakland Avenue. He was released Dec. 21 after serving four months of his sentence.
Hanson and Newport were "known acquaintances" and "had associated together with other friends the evening prior to her death," Hewlett said. "They were partying at an apartment and then went to a bar."