MARTINEZ -- A former Pinole man charged with murdering his girlfriend in 1999 is once again eligible for a death penalty prosecution -- this time under a "lying in wait" special circumstance allegation recently filed by the Contra Costa District Attorney's Office.

The office has not announced whether it will seek capital punishment against Raymond Wong, who is facing trial on murder charges in the death of 21-year-old Pinole resident Alice Sin. The office last sought the death penalty -- and got the death verdict -- against Richmond resident Nathan Burris for killing two people at the Richmond-San Rafael Bridge toll plaza in 2009.

A preliminary hearing judge in February rejected a special circumstance murder allegation that Wong killed Sin for financial gain. The judge said there wasn't enough evidence to support a prosecution theory that Wong directed Sin to take out a $2 million insurance policy against her death as he was planning her murder.

The prosecution added the "lying in wait" special circumstance to Wong's charges, which again makes him a candidate for capital punishment. The theory behind the new allegation is that Wong, equipped with night vision goggles, took Sin to a remote area of the Nevada desert against her will and shot her several times in a premeditated attack.

Sin was the mother of Wong's infant son and may have been in the early stages of a second pregnancy when she was killed. She is believed to have been shot on Nov. 21, 1999, the day before Wong reported her missing and two months before her body was found in Churchill County, Nev.

Wong was a suspect in the homicide early on, but he wasn't charged with murder until December 2011.

There was testimony at his preliminary hearing that on the day Sin died, a couple at a Churchill County truck stop saw Sin and Wong fighting outside while a second woman sat in Wong's car.

Authorities suspect the second woman was Jessica Tang, Wong's other girlfriend, with whom he had also fathered a child that year. Wong and Tang were living together within days of Sin's disappearance and had all of Sin's belongings in garbage bags, according to preliminary hearing testimony.

Wong, who is being jailed without bail, appeared in Contra Costa County Superior Court on Monday. He delayed entering his post-preliminary hearing plea as he assesses whether he can continue to afford his private defense team.

He is scheduled to return to court March 25 to announce whether he is keeping the attorneys.

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