The ex-husband of accused murderer Maryann Acker finished his second day on the witness stand yesterday, claiming that she pulled the trigger in two 1978 murders committed here and in California.

William Acker underwent more than a day of cross-examination by his ex-wife's lawyer, Keith Shigetomi, saying at one point that he lied under oath in 1991 when he told California parole authorities that he shot and killed Lawrence Hasker here in 1978.

Yesterday, Acker said that he didn't kill Hasker and claimed that he lied because he was trying to help his wife win parole.

He also said that she used the same .38-caliber pistol that killed Hasker to kill Cesario Arauza in California five days later.

But Shigetomi forced Acker to acknowledge that he entered a no-contest plea in California to charges that he used the gun to murder Arauza.

Both Ackers were convicted of murdering Arauza, but Maryann Acker was not charged with use of the gun in that case.

The Circuit Court trial is a reprise of one held here in 1982, when Maryann Acker, largely on the strength of William Acker's testimony, was convicted of murdering Hasker. William Acker was only charged with robbery in the case after he agreed to testify against her.

Maryann Acker, who now uses her maiden name, Maryann Bray, was granted a new trial here after Circuit Judge Michael Town ruled that jurors in the original trial weren't given sufficient background information about William Acker's role in the Arauza case.

An acquittal verdict here would improve her chances of winning parole from a California prison.

William Acker has testified against other inmates in California criminal cases and is now in protective custody, held under an assumed name.

Video cameras and still photographers have been banned from taking his picture while he's on the witness stand here, based in part on Acker's claim that such coverage would endanger his life.

"Any inmate in the Hawai'i prison system who might learn I have been a cooperating witness would gain considerable notoriety and status by taking my life or causing me serious bodily injury," William Acker said in court papers.

The trial continues Monday.