Lancaster Man Guilty in Slaying of Fiancee : Courts: Christopher Rowland has been diagnosed as paranoid and at times claimed to be a vampire slayer.

A 23-year-old Lancaster man, who has at various times claimed to be a mind reader, fallen angel and vampire slayer, was convicted Thursday of second-degree murder in the 1990 slashing death of his fiancee.

Christopher Michael Rowland, 23, blinked rapidly, threw back his head and groaned in disbelief as the jury returned its verdict after two days of deliberations. He was acquitted of premeditated, first-degree murder.

Superior Court Judge Michael R. Hoff ordered Rowland to return to court Dec. 5 for sentencing. A second-degree murder conviction carries a maximum sentence of 15 years to life in state prison.

Rowland had known 18-year-old Roberta Mosentheim just a few weeks when her body was found by a maid on a motel room bed on Feb. 12, 1990. Her throat had been slashed, and she had also been stabbed several times in the neck, chest and abdomen.

“I think the verdict was right,” said Frances Largent, the victim’s mother, who said her daughter “was a very sensitive young lady” who had hoped to become a veterinarian. “She hadn’t known him very long. . . . He was the first guy she ever cared for.”

According to testimony by prosecution witnesses, Rowland met Mosentheim’s brother, Kurt, on a bus and soon afterward, Mosentheim fell in love with the muscular young man with blue eyes and curly blond hair. Within days of meeting, they were making plans to marry.

Some family members initially were concerned about the relationship because they believed Rowland had a criminal past. But Largent said, “My daughter always was taught to give everybody the benefit of a doubt.”

Trusting Rowland cost Mosentheim her life, Deputy Dist. Atty. Mark Collier alleged during the two-week trial. Collier contended that Rowland, who did not testify, had told other people several versions of his alibi--that she was killed by gang members, that she was killed by robbers, that he’d stabbed a “green monster.”

Mosentheim’s father told police he last saw his daughter at about 10:30 p.m. the evening before she died. He said she and Rowland were headed toward a motel on Sepulveda Boulevard, a few blocks from the Mosentheim family’s Van Nuys home, to discuss their plans for the future.

Rowland was gone when Mosentheim’s body was found. But a T-shirt later identified as Rowland’s was draped over her body.

Mosentheim’s father later gave police a camera and told them it was discovered among Rowland’s possessions, found in a car where he’d been sleeping. Police developed a roll of film found inside, which included pictures of Rowland wearing the goat’s-head T-shirt.

Police also found blood on Rowland’s shoe tops and laces, but it could not be matched with the victim’s because blood samples taken from her body were mishandled and had decomposed, according to testimony.

A statement Rowland gave police after his arrest also was not used at the trial because detectives spoke to him even after he asked four times for a lawyer. In the statement, Rowland told police Mosentheim was a vampire.

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Defense attorney Mark E. Montpas said police concocted the vampire story and put words in his client’s mouth. Montpas added that he would appeal the jury’s verdict because the evidence was insufficient.

Following his preliminary hearing, Rowland was twice found incompetent to stand trial on the grounds that his mental condition prevented him from understanding the proceedings or assisting in his defense. At one hearing, he claimed to be able to read minds and said he was a fallen angel. He claimed Jesus Christ had spoken to him three times.

Rowland was diagnosed as paranoid and depressed--conditions apparently made worse by drug use, a psychiatrist testified at one of the hearings. He had been confined at Patton State Hospital, but has received no treatment during the 18 months he has spent at County Jail, his attorney said.