SAN DIEGO (CNS) - A medical student who plied an already intoxicated Orange County man with drugs, then killed him during a sexual assault, was sentenced Friday to life in prison without the possibility of parole.

Philong Huynh, 41, was convicted in June of the Jan. 26, 2008, murder of 23-year-old Dane Williams of Huntington Beach, who came to San Diego for a trade show.

Jurors found that the murder happened while the defendant was engaged in the sodomy and oral copulation of an intoxicated victim.

Huynh, of City Heights, was also convicted of sodomy and oral copulation of an intoxicated person for a 2009 sexual assault on a 20-year-old Navy Corpsman who came forward more than a year after Williams' death.

"Losing Dane was gut-wrenching. I ache for him every day," said Williams' mother, Valen.

She called Huynh a "coward" and a "poor excuse for a human being."

"I honestly cannot fathom how your evil mind works," the victim's mother told the defendant. "Dane is not coming back. You made sure of that. After today, I will never, ever think of you again."

Friends said Williams wanted to be a professional surfer.

Williams' father, Jim, called Huynh a "predator" who will spend his time in prison "at the bottom of the inmate food chain."

According to a probation report, Huynh would be a high risk to commit another sexual offense if released from custody, said Judge Robert F. O'Neill.

Deputy District Attorney Gretchen Means told the judge that Huynh's sexual crimes against Jeremiah -- the Navy Corpsman -- left him "irrevocably altered and scarred."

The prosecutor said the defendant manipulated the young man and violated him "time and time again."

In his closing argument, Deputy District Attorney David Hendren said deputy medical examiners determined that Williams' probable cause of death was asphyxia. Because doctors couldn't determine how Valium got into the victim's system, they listed the manner of death as undetermined, Hendren said.

Hendren said Huynh was in his third year of medical school, had studied pharmacology, knew a lot about drugs and had prescriptions for Benzodiazapam and Clonazepam, He said the defendant acted like a "wolf in sheep's clothing" by giving Williams a depressant that rendered him unable to fight off a sexual assault.

Williams' body was found three days later in an alley two blocks from the home that Huynh shared with his mother.

The prosecutor said Williams, Jeremiah and four other men who testified at trial were heterosexuals who fell victim to Huynh's con game between 2007 and 2009. Hendren said Huynh would meet young, good-looking straight men, gain their trust by talking about women, then offer to buy them drinks and take them to strip clubs in Mexico.

Once he got the victims alone, Huynh would slip them a depressant to knock them out, making them "basically unconscious," the prosecutor said.

Jeremiah said he felt disoriented for five days after being drugged and sexually assaulted by Huynh, the prosecutor said.

In August 2009, sperm found on Williams' body was matched to sperm found on the Navy Corpsman, and Huynh was arrested the following month.

Defense attorney Terry Zimmerman said the defendant didn't kill Williams. She said there was evidence that Huynh and Williams were together the night the victim died, and that the defendant woke up next to the dead man and disposed of the body, placing it where it could be found.