A man accused of murdering a couple to steal their yacht was charged with killing another man while on a work furlough from jail.

The new complaint against Skylar Julius Deleon (search), 26, was filed late Thursday at the Harbor Justice Center in Newport Beach. It claims that on Dec. 27, 2003, he killed a man he met while both were serving time at the Seal Beach jail.

Deleon at the time was spending nights in jail while serving a one-year burglary term, but was allowed to work during the day. The man he allegedly killed, Jon Peter Jarvi (search), was serving a four-month federal sentence for counterfeiting, said Orange County deputy district attorney Matt Murphy.

According to the complaint, Deleon allegedly drove Jarvi, 45, to Mexico under the pretense of completing an easy money business deal.

Jarvi, a pilot who also made custom jewelry, had $50,000 in cash from recently refinancing his condominium and pawning his van, Murphy said.

Jarvi's body, its throat slit, was found near the Mexican highway that leads up to the Tecate border check.

Cell phone records show that Deleon traveled to Mexico the day Jarvi was killed, according to police reports.

Deleon returned late to the Seal Beach jail that night, but was allowed inside by a civilian jailer, Murphy said.

That jailer, Alonso A. Machain (search), 25, is now a co-defendant in the Nov. 15, 2004 kidnap and murder of Thomas Hawks (search), 57, and his wife Jackie, 47.

While posing as potential buyers of the Hawks' yacht, the Well Deserved, Deleon, his wife, Jennifer Henderson-Deleon (search), and a third man allegedly overpowered the couple, chained them to a 60-pound anchor and tossed them overboard into the ocean. Their bodies have never been found.

The Deleons and John F. Kennedy, 39, all of Long Beach, were ordered to stand trial this week for the Hawks' murders.

Machain, the jailer, and Myron Gardner, 42, of Long Beach, also are charged in the slayings.

Henderson-Deleon also was charged with accessory to murder after the fact in Jarvi's killing.

Skylar Deleon's cousin, Michael W. Lewis, Jr., was arrested Thursday afternoon at his home in Oatman, Ariz., on charges that he was an accomplice in that crime.