Copyright 1997 Times Mirror Company   Los Angeles Times June 25, 1997, Wednesday, Ventura County Edition SECTION: Metro; Part B; Page 11; Zones Desk LENGTH: 667 words HEADLINE: WOMAN CONVICTED IN FRIEND'S 1985 SLAYING DENIED PAROLE BYLINE: JOSE CARDENAS, TIMES STAFF WRITER  DATELINE: ARLETA BODY: A woman who helped beat and drown a teenage friend 12 years ago in Angeles National Forest--and then moved in with the dead girl's mother, pretending to assist in catching the killers--was denied parole Tuesday in her first try at freedom. A three-member panel of the Board of Prison Terms ruled that Karen Severson, 29, is still a danger to society. The decision "was based on the seriousness of her crime," said Lt. Robert Sebald, assistant warden at the California Institution for Women at Frontera. "She has not really dealt with what really happened," said Tamia Hope, the deputy district attorney who tried the case and argued against the release. " The board's concern was that the crime was calculated." Severson and Laura Doyle were sentenced in March 1990 to 15 years to life in prison for second-degree murder in the death of Michele "Missy" Avila--a 17-year-old Arleta girl--in a fight over a boyfriend. Avila's body was found with a 100-pound log holding her head under water in a forest creek in October 1985, but the case was not solved until three years later. At the time of the slaying, the three teens were childhood friends who liked to party--frequently at Colby Canyon, the remote area where the body was found. Avila and Severson had been transferred from San Fernando High School to San Fernando Mission--a continuation school. Prosecutors alleged during the 1990 trial that on the day of the slaying, Severson and Avila drove to their hangout followed by Doyle and Eva Chirumbolo--a fourth friend who was not prosecuted--in a second car. The four then walked down an embankment to a creek. At some point, an argument about a boyfriend whom both girls had dated broke out between Severson and Avila, prosecutors said. * The girls attacked Avila--cutting off her hair, the prosecutors said. Then, they held her head under eight inches of water until she drowned--leaving her pinned by the four-foot long log. When Avila was reported missing, Severson and Doyle cooperated with the police; Doyle explained that she had left Avila at Branford Park talking with two young men while she went to get gas for their car. The three were gone when she came back, she said. After the funeral, Severson moved in with Irene Avila, the dead girl's mother, authorities said. Over the next three years, she and Doyle gave conflicting stories, investigators said. At one point, Doyle said she had left Avila at a church, not the park. Investigators said they suspected the girls knew something they were not telling, though they did not suspect they were the actual killers. The girls were finally arrested when Chirumbolo--who prosecutors said returned to the car before the actual killing took place--came forward in July 1988. The case inspired a novel and a television movie. Tuesday, some of Avila's family members spoke against the release. Severson's family also was present. Severson will again be eligible for parole in four years, according to authorities.