A Buffalo mob informant is expected to plead guilty to a reduced charge in a murder case before the end of the month, according to law enforcement sources.
William Koopman, 33, a former Buffalo garbage collector, would plead guilty to a reduced charge of first-degree manslaughter and receive less than the maximum 25-year term in the fatal shooting of John Pinelli, 24, in 1986, sources said.
Under a June 1987 indictment, Koopman -- considered a productive informant -- faces a life term with a minimum sentence of 15 to 25 years if convicted as charged of second-degree murder.
The details of the deal "will probably be resolved within the next two weeks," with proceedings in State Supreme Court before the end of the month, one source said.
Although Koopman has been identified by other informants as the "triggerman" in the Pinelli slaying, he may not be forced to admit in court to being the actual killer, sources said.
Under a charge of first-degree manslaughter, Koopman could admit he intentionally tried to hurt Pinelli and caused his death in the process, sources said.
Pinelli, considered by authorities as a small-time Buffalo crook, was shot in the back of the head and dumped into a ditch off Jennings Road in the Town of Eden early on the morning of Sept. 29, 1986.
Koopman's former co-defendant, Luciano Charles "Dilly" Spataro, 57, Pinelli's father-in-law, reportedly wanted Pinelli dead because he feared he would implicate Spataro's son, Curtis, 32, in a Buffalo robbery and he suspected he was abusing his daughter, Cindy, according to sources.
Carmen Spataro, 28, another son of Luciano Spataro, was a witness against Koopman in the Pinelli slaying.
Koopman is now the chief witness against Luciano Spataro in the April 1985 slaying of Amherst bodyguard Robert DiGiulio, 32.
In protective custody since mid-May and cooperating with state and local authorities in five murder cases, according to sources, Koopman is expected to begin cooperating with federal authorities shortly.
Under the plea, he would spend virtually all of his sentence in a federal prison as a member of the federal witness-protection program, sources said.
Koopman would receive a new identity, even in prison, as a participant in the federal program. But that "is still a couple months off," one source said.
Authorities would like to schedule Koopman's plea before the start of the State Supreme Court murder trial or trials of Spataro and Anita DiGiulio Marvin, 42, of Amherst, the remarried wife of the slain DiGiulio. The two may seek separate trials, according to their attorneys.
The DiGiulio murder trials, which may begin before the end of the month, will mark the first time Koopman will be asked to testify in court since becoming an informant.
District Attorney Kevin M. Dillon and Frank J. Clark, first deputy district attorney, and the key prosecutor in the DiGiulio case declined to comment on the plea talks for Koopman.
However, law enforcement sources confirmed that Clark and Dillon have been conducting closed-door meetings in recent weeks with Richard J. Barnes, Koopman's court-assigned lawyer. Barnes, a former assistant Erie County district attorney, also declined to comment.