DNA TIES SUSPECT TO DEATH OF WOMAN A.V. MAN IS ARRESTED IN PROSTITUTE'S SLAYING.

Byline: Greg Botonis Staff Writer

LANCASTER - DNA evidence linked a registered sex offender to the 1999 slaying of a 40-year-old Lancaster woman who worked as a prostitute and was found beaten to death on a desert dirt road, authorities said.

Ronald Lynn Rook, 37, of Lancaster was arrested Wednesday in Santa Clarita by Sheriff's Department surveillance deputies who have been following him since his DNA was linked last month to the killer of Twila Ann Martin, a mother of two who family said tried but was unable to kick a drug addiction.

``This is a guy who preys on prostitutes,'' said homicide Detective Sgt. Tim Miley , who has been working on Martin's case for five years. ``Typically when prostitutes become the victim of a crime, they don't come forward so that made it tough.''

The ex-convict, who was arrested on suspicion of rape and murder, was jailed without bail, officials said.

Martin's body, clad only in a T-shirt and bra, was found Feb. 28, 1999, in the middle of a dirt road near Avenue L-8 and 15th Street East. She had been raped and severely beaten.

Martin had vowed to change her life. She married and moved to Ohio, but divorced soon after. Both her children were taken away from her when she started using drugs again, friends said.

Investigators initially arrested an ex-convict friend of Martin whose home she had visited the morning before she was killed. But he was quickly cleared based on DNA evidence.

Rook, who got out of state prison in 1997 after a conviction for assault with a firearm, was not immediately linked to Martin's slaying because the DNA sample that had been obtained previously from him was too small for testing, officials said.

The Sheriff's Department crime lab switched this year to a new process able to test smaller samples. A computer database linked Rook's DNA to Martin's killer, authorities said.

Rook had been employed on an assembly line, officials said.

``I've been working this case for five years,'' Miley said. ``I was very excited to get the word of the match.''

Detectives said they are investigating unsolved rapes around Lancaster to see if Rook was responsible.

Martin's death was one of at least five between 1994 and 1999 involving women who used drugs and worked as prostitutes around Lancaster.

A convicted Lancaster rapist suspected of kidnapping and raping prostitutes was investigated in the deaths of three women in 1996 and 1997, but DNA evidence cleared him of the killings.

Martin died while that man was in jail awaiting trial on rape and kidnapping charges, for which he was convicted and sentenced to 181 years to life in prison. Two of the other women died while Rook was in prison on the assault charge, records show.

At the time, detectives said they had no proof that a single killer was responsible for the five women's deaths. Drug-addicted prostitutes live dangerous lives, vulnerable to boyfriends, customers and drug suppliers, detectives said.

Greg Botonis, [phone]

gregory.botonis(at)dailynews.com

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Photo:

(color in AV edition only) Ronald Lynn Rook

Jailed without bail