RIVERSIDE, Calif. -

A 22-year-old former UC Riverside student accused of attempting to arrange the murders of two ex-boyfriends must stand trial on solicitation of murder charges, a judge ruled today.

Barbara Wu was arrested in May following a UC Riverside police investigation that allegedly uncovered instances in which the defendant had sought to have two men killed.

Following a preliminary hearing at the Riverside Hall of Justice, Riverside County Superior Court Judge Charles Koosed found there was sufficient evidence to bound Wu over for trial on two counts of solicitation of murder, as well as one count each of witness intimidation, stalking, felony vandalism, misdemeanor vandalism and making criminal threats -- also a misdemeanor.

Koosed left the defendant's bail set at $500,000 and scheduled a post-preliminary hearing arraignment in the case for Aug. 22.

Wu is being held at the Smith Correctional Facility in Banning.

Her preliminary hearing began Friday and concluded this afternoon. The defense suggested Wu intended to testify, but she elected not to, and defense attorney Rajan Maline did not call any witnesses.

Last week, Wu's two alleged targets testified about their experiences with the defendant, whom one of them characterized as volatile and persistent in pushing to get what she wanted.

He said the high school honor roll student asked him to kidnap her former boyfriend -- who broke up with her via email -- and dispose of the body. When the man related the conversation to police, they asked him to wear a wire and record his next encounter with Wu, during which she allegedly incriminated herself, according to testimony.

According to the District Attorney's Office, the first alleged victim came forward after the case became public, telling investigators that he believed he was the intended target.

``He advised that while he dated Wu in 2009 and 2010, she asked him to kill another former boyfriend,'' said District Attorney's Office PIO John Hall.