RICHMOND -- Diablo Valley College student Alice Sin was seen arguing with her live-in boyfriend, Raymond Wong, at a Nevada truck stop around the time she disappeared in November 1999, according to court testimony Wednesday.

The truck spot was located not far from the Churchill County, Nev., desert where the 21-year-old Pinole woman's body was discovered a month later, a former Churchill County investigator said at a preliminary hearing for Wong.

Wong, a 41-year-old computer engineer, was charged with murdering Sin for financial gain in late 2011 after police said new evidence had been discovered in the 12-year-old murder mystery.

The Contra Costa District Attorney's Office has not yet announced whether it intends to seek the death penalty in the special circumstances case in which Wong is accused of killing to collect on a $2 million insurance policy he took out against Sin's death.

Wong shared a son with Sin and told family members that she was four months pregnant when he reported her missing on Nov. 22, 1999. Investigators on Wednesday recalled finding her partially nude and mutilated body by a badgers' nest off a rural road on Jan. 24, 1999. She had been shot four times, and had Monopoly money marked with "NWO" and "ZOG" stuffed in her bra, a retired detective said Wednesday.

Police have previously said that Wong wrote the letters -- symbols significant with the white supremacist movement -- to misdirect the homicide investigation. Police are expected to testify at the preliminary hearing that Wong did an Internet search on NWO and ZOG three days before Sin's death.

Upon seeing Sin's picture in a local newspaper in January 2000, a Churchill County couple called police to report that they had seen Sin and an Asian man fighting at a truck stop the week of Nov. 22, 1999. The woman picked out Wong from a photo lineup without hesitation, a former detective said.

The couple reported a second Asian woman was sitting in Wong's car as Wong and Sin fought outside for about a half-hour. There has been no testimony as to whether the second woman is believed to have been Jessica Tang, whom he married days after Sin's body was found.

Prosecutors have said the love triangle was a factor in the homicide.

Wong moved to China in 2009, long after he was incarcerated in federal prison for having child pornography that detectives investigating Sin's disappearance found on his home computer.

He had just re-entered the country in December 2011 to visit his sick father when he was arrested on an old warrant for falling out of compliance with his sex offender registration, police have said. Within days, he was charged with Sin's murder.

Testimony in the hearing continues Feb. 20.

Contact Malaika Fraley at 925-234-1684. Follow her at Twitter.com/malaikafraley.