Searchers with bloodhounds combed the mountains of southern West Virginia yesterday for Lynette (Squeaky) Fromme, a follower of mass murderer Charles Manson who vanished Wednesday from the federal prison where she was serving a life sentence for the attempted assassination of President Gerald R. Ford 12 years ago.

Officials at the Federal Correctional Institution for Women in Alderson, W.Va., said two searches of the 96-acre prison grounds had turned up no sign of Fromme, who still corresponds regularly with Manson and wears the red bandanna that marked her as a member of his "family." Manson is imprisoned in California.

Spokesman Lane Wagaman said there is a "possibility" that Fromme had outside help, although she has had no visitors in more than a year and her letters, which are monitored by prison officials, contained no suggestions of an escape plan.

Roadblocks have been set up and dozens of law officers are systematically searching the mountains around the prison, which is surrounded by an eight-foot fence and sits in rugged terrain about 80 miles southeast of Charleston. U.S. marshals in all 50 states have been notified of the escape.

"We consider her potentially dangerous, but there is no evidence that she's armed, and in the eight years she has been here she has demonstrated no aggressive or assaultive behavior," said Wagaman, the prison's chief psychologist.

Fromme, 39, was convicted of aiming a .45-caliber pistol at Ford on the grounds of the California state capitol in Sacramento on Sept. 5, 1975. A Secret Service agent grabbed the weapon before it could be fired, and Ford was not harmed. Ford also escaped injury 17 days later when Sara Jane Moore, a political activist, fired a revolver at him in San Francisco.

In 1979, Moore also escaped from the Alderson prison but was recaptured less than four hours later, near the posh Greenbriar Hotel in White Sulphur Springs, W.Va. She is now imprisoned in California.

A Secret Service spokesman said agents are "taking appropriate action" after Fromme's escape, although he said there has been no suggestion that Ford, who now lives near Palm Springs, Calif., is in any danger.

Fromme, a slightly built red-head dubbed Squeaky by Manson because of her high-pitched voice, became a bizarre symbol of counterculture terrorism at her 1975 arraignment and trial, most of which she refused to attend. Clad in a bright red, druid-like robe, she was repeatedly ejected from the courtroom for her rambling discourses on environmental problems. At her sentencing, she hit the prosecutor with an apple.

Fromme was initially imprisoned at Alderson, but was moved to a federal women's prison at Pleasanton, Calif., in 1978. She was returned to Alderson a year later after she struck another inmate with a hammer.

Since then, Fromme has apparently been a model prisoner. Although she was eligible for parole consideration two years ago, prison officials said, she declined to appear before a parole board.

Wagaman said prison employes last saw Fromme at 8 p.m. Wednesday. "At the 9 o'clock check she was found missing," he said. One inmate claimed to have seen Fromme at 8:50 p.m., Wagaman said, but the report has not been confirmed.

"There is no physical evidence of an escape," he said. "No break in the fence, no material caught on the fence."

Two bloodhounds also were unable to find the exit area, he said, adding that recent wet weather made it more difficult for the dogs to track Fromme's scent.

The Alderson prison resembles a college campus, patterned after Bucknell University in Pennsylvania. Fromme was assigned to one of the cottages that house the prison's 935 inmates.

"She's been no problem at all," Wagaman said. "She's pretty much a loner, low-key and reserved." He declined to say if Fromme had been under psychiatric care.

Wagaman said Fromme appeared to have no close friends at the prison since the parole in 1985 of Sandra Good, her former roommate and fellow Manson follower. Good, convicted of making telephone threats to several businessmen, lives in Vermont, where she was questioned yesterday by Secret Service agents.

Since Good's release, "Lynette's not evidenced any close relationships," Wagaman said. Wagaman said prison officials and inmates usually refer to Fromme as Lynette, rather than Squeaky, although some call her "Red" for the bright bandanna she wears.

According to prison officials, there have been seven previous escapes from Alderson in the last two years, involving 14 inmates. Two inmates, both convicted of drug offenses, remain at large. Some of the others were caught as far away as Texas and Oklahoma.

Fromme first gained notoriety as a member of the "family" of Manson, who was sentenced to life imprisonment for the 1969 mass murders of actress Sharon Tate and six other people.

During Manson's trial in Los Angeles, she and Good, neither of whom was charged in the Tate slayings, carved X's in their foreheads to demonstrate their support. Fromme still bears the scar.

In 1973, Fromme and three other Manson followers were accused of murdering a woman who had been involved with the "family." The charge against Fromme was dropped for lack of evidence.