The bizarre case of the Hillside Strangler may have been transformed into the even stranger Case of the Hillside Stranglings by the arrest here of a quiet Beverly Hills handyman and a convicted Boston bank robber.

Los Angeles police late Thursday booked Peter Mark Jones, a 36-year old handyman, on suspicion of murder in the deaths of two young women who were listed among the supposed strangler's 13 victims. Recently installed Police Chief Daryl Gates said information provided by George Francis Shamshak, 27-year-old Massachugetts convict who is serving a bank robbery term, implicated both men in the two kiilings.

Gates, who headed the 92-member Hillside Strangler Task Force before his appointment as chief March 24, claims that the arrest of the two men is "major breakthrough" in the long investigation. If he is right - and neighbour Jones nor Shamshak has formally been charged in any of the murders - it means police were wrong in linking the 13 deaths to a single killer or murder team.

Police emphasized yesterday that Jones is not a suspect in 11 of the 13 killings. Shamshak was in priso when three of them were committed Neither man fits composite drawings that were made of two men who drove off with one of the victims last December.

Some of the Hollywood prostitues whose friends were murder victims have scoffed from the beginning at the theory of a single strangler. Police here linked all the crimes because of the method of killing and because of the method of killing and because victims were mutilated in a way that police consistently have refused to disclose. When some of the gruesome details were printed in Newsweek, the magazine's account was denounced as inaccurate,

However, the arrests Thursday cast some doubt on past official versions of the killings. Shamshak reportedly told Massachusetts investigators that Jones had bludgeoned one of his victims to death.

One of the murders for which the pair is being investigated is the Nov. 10 slaying of Jill Terry Barcomb, whose nude body was found along a roadway in West Los Angeles.

Barcomb, who came to Hoolywood after a New York conviction for prostitution, was the supposed fifth victim of the Stangler. An autopsy after her death provoked an unusual feud between the police and the Los Angeles County coroner's office, which said the victim had been bludgeoned to death and not strangled.

According to police sources Friday, Shamshak made statements to Massachusetts investigators in which Jones claimed to have hit one of the women on the head with a blunt instrument. He is also supposed to have said that he strangled one victim and stabbed another.

There's no record of any stabbing victim. The strangling killing for which Jones is under investigation is the Nov. 18 murder of 17-year-old Kathleen Robinson - the supposed sixth victim of the strangler.

Unlike all but one of the other 13 victims, Robinson was found fully clothed. Her body was deposited in the flatland business section of the city's post Wilshire district. Most of the victim's bodies were dumped on hillsides in parks or residential areas.

Though the murders have provoked the most intensive manhunt in the city's history, the break in the case, if a braak it is, came 3,000 miles away in a Massachusetts, near the city where the Boston Strangler killed at least 13 women more than 15 years ago.

Shamshak, serving a four-to-five year term for armed robbery, escaped last October from a minimum security prison in Masschusetts and came to Los Angeles where he renewed his acquaintance with Jones, a boyhood friend from the working-class Roxbury section of Boston.

Shamshak returned to Massachusetts where he was recaptured last month in Cambridge. Two days after his arrest he threatened to swallow razor blades unless he was allowed to talk with state investigators about the Hillside stranglings.

The investigators, accustomed to false confessions in the Boston Strangler case, brought along their lie detectors. Convinced that Shamshak was talking about actual crimes, not fantasies, they reported their findings to Los Angeles police.

Los Angeles police brought Shamshak here on March 17 and took him around with them on a series of stage-outs for Jones, who was vept under constant surveillance. Reportedly, Shamshak also was taken to the scene of the Barcomb and Robinson killings.

As police sources reconstructed the narrative, Shamshak said he drove Jones' 1966 Ford van while Jones killed the women. Throughtout the long hunt for the strangler, police have been looking for a van which they said was spotted near the areas from which various victims disappeared.

As yet, police have offered no motive for the killings and have declined to comment on wheather there is evidence beyond Shamshak's accusation linking Jones to the murders. Jones surrendered quietly when he was approached by police and reportedly is cooperating with the investigation. Shamshak is being held in a federal prison in San Diego held in a federal prison in San Diego.

Jones was described as "quiet orderly and a hard worker" at the medical building where he was a maintenance man and at the Beverly Hills apartment where he lived. The building superintendent at the medical building, Pauline Staratt, was quoted by the Los Angeles Herald Examiner as saying of Jones that she would "swear on 100 Bibles that he is innocent, because I know of his comings and goings. He's been at our office everyday."

Under California law, formal charges cannot be filed over the weekend. The Los Angeles district attorney must charge Jones with the crimes by Tuesday or release him.