A Montgomery County Circuit Court jury yesterday rejected the insanity defense of a convicted killer who, according to a pyschiatrist, had six alternate personalities, one of which was a demonic dog named Tufu.

The jury returned its verdict on the insanity plea after about two hours of deliberations in the trial of Michael D. Proctor, a former medical student. On Monday, in the first stage of the trial, the same jury found Proctor guilty of the April 17, 1989, slaying of an ex-girlfriend and the attempted murder of her boyfriend.

In the insanity phase, defense attorney Alan C. Drew sought to prove his client was not criminally responsible for the crimes because he suffered from a multiple personality disorder.

But the jury did not believe the claim. Juror Kip Shapiro of Silver Spring said the jury believed Proctor, 28, was a "troubled man," but the panel "was not satisfied" he had a multiple personality disorder.

Shapiro said an edited version of a videotape shown to the jury Tuesday to demonstrate the "demonic eyes" of Tufu had little bearing on the verdict.

Judge J. James McKenna set a March 7 sentencing for Proctor, who faces two life terms on the first-degree murder and attempted first-degree murder convictions. If the jury had accepted the insanity defense, Proctor would have been committed to a mental institution for treatment. He is being held without bond in the county jail.

In an emotional closing statement yesterday, Drew asked the jury to seriously consider the multiple personality diagnosis of Bethesda psychiatrist Richard S. Epstein. "Do not allow yourself to be ridiculed into abandoning the defendant," Drew said. "There is this idea that this is made up. It's hokey. But it's not."

On Tuesday, Epstein testified he believed two of Proctor's alternate personalities -- Tufu, a Pekingese dog, and Clarence, a Satanic follower -- had committed the crimes. "Clarence and Tufu in concert fired the gun," Epstein said. "Tufu was the hatchet man for Clarence."

Proctor has never admitted guilt in the killing of Sandra Wright, 24, and the attempted murder of Johnny Dinkins, 27, who was shot three times in the head.

In closing statements, Prosecutor John McCarthy said Proctor was a "con man" who had feigned multiple personalities to escape punishment. McCarthy said Proctor had told a former cellmate of his plans and had read books and watched a television show on the subject.

McCarthy said rage and jealousy motivated Proctor to shoot his victims. "He was enraged about what was happening. That's not a mental illness. That's a human emotion."