Menendez Gun Link Pursued : Murders: Authorities believe they have found shop where brothers allegedly bought guns used in parents’ slayings. Handwriting samples of suspects will be sought.

Authorities believe they have discovered the shop where Lyle and Erik Menendez allegedly purchased shotguns used to murder their parents in Beverly Hills, and they are attempting in court to obtain handwriting samples that would establish the link, The Times has learned.

While sources familiar with the investigation said that the murder weapons have not been found, detectives have discovered in a San Diego County gun shop paper work that could turn into important evidence to establish that the brothers purchased two 12-gauge shotguns used to slay their parents.

Lyle, 22, and, Erik, 19, were arrested last March 8 in the murders of their parents, Jose and Kitty Menendez, and are being held without bail. Each faces murder charges with special circumstance allegations--multiple murders, killing for financial gain and lying in wait--that could result in the death penalty if convicted.

The two defendants have pleaded not guilty. No date has been set for their preliminary hearing.

The Menendez couple were slain while watching television in the family room of their mansion on Elm Drive on the evening of last Aug. 20. Menendez, 45, was chief executive of Live Entertainment Inc. of Van Nuys, a video and music distributor.

The murder weapons, two 12-gauge shotguns, were purchased in a gun store in San Diego County shortly before the murders, the sources said. The name of the shop was not immediately known.

The prosecutor in the case, Los Angeles County Deputy Dist. Atty. Eliott E. Alhadeff, has asked for new handwriting samples from the brothers. Alhadeff would not comment on why he wants the samples, but sources said it was in connection with the sale of the shotguns.

Neither attorney for the defendants, Gerald Chaleff nor Leslie Abramson, would comment on the case Tuesday.

Several gun shop owners along the Interstate 5 corridor in San Diego County told The Times that investigators canvassed the area for the weapons about a month ago.

Under federal law, to purchase a weapon, an individual must fill out a “4473” form for the gun shop owner. It requires the buyer to provide name, address and other vital information and has to be signed by the purchaser, who must also provide an identification card with a picture, usually a driver’s license.

Separately on Tuesday, Santa Monica Superior Court Judge James A. Albracht ordered the county coroner to release autopsy reports on the slain couple, based on motions filed by lawyers representing two television networks, NBC and ABC.

According to the reports, the killers used two types of shotgun ammunition, large pellets and birdshot. Five blasts hit Jose Menendez, 10 blasts hit his wife, wrote Dr. Irwin L. Golden, who performed the autopsies.

Sources have said knowledge that two types of ammunition were used in the slayings could be important evidence at trial, lending credence to the belief that two killers were involved. Previously, it was revealed that a former Princeton classmate of Lyle Menendez turned over an expended shotgun shell allegedly found in one of Lyle’s jackets to detectives last fall.

According to the coroner’s reports, apparently one of the killers came up behind Jose Menendez and fired a round that blew off the back of his head, killing him instantly.

Early in the murder investigation, it was believed that a shotgun had been fired in the victim’s mouth, because of the nature of the fatal wound. It led to assumptions by some that the double killing was mob-engineered. But, according to the autopsy report, the trajectory of the blast was “back to front.”

Jose Menendez, dressed in a sweat shirt, shorts and leather shoes, according to the report, also was hit in both arms and the chest.

“There was evidence of close-range firing . . . ,” the report said.

Kitty Menendez, dressed in a sweat shirt, jogging pants and sneakers, was struck by 10 blasts, according to Golden’s report. Fatal blasts of birdshot pellets hit her in the face and chest, he said.

Investigative sources have said that Kitty Menendez was found a few feet from a sofa on which the couple were sitting. The angle of the shotgun blasts, according to the autopsy, support investigative theories that she was slain while attempting to flee.

William Eckert, a nationally known forensic expert who examined the autopsy reports at the request of The Times, said it appeared the killings were done by amateurs.

“It seems to me (the 15 shotgun blasts) wasn’t necessary,” he said in a telephone interview from his Wichita, Kan., home. “It had to be done by amateurs. This was overkill.”