A Queens man has pleaded guilty to manslaughter in the killing of an 81-year-old War World I veteran 46 years ago, officials said.

Martin Motta, 75, will likely be sentenced to 20 years in prison for the 1976 murder of George Clarence Seitz, a veteran whose remains were found in the backyard of a Richmond Hill home in 2019, Queens District Attorney Melinda Katz said Tuesday.

Police had been directed to the body in March 2019 by an anonymous tipster, who said she’d recently remembered the night when, back in the 1970s, she watched her mother's boyfriend chop up and inter a body. At the time, she told police the victim had some connection to a local barbershop.

A two-year long investigation identified the remains as Seitz, who was last seen leaving his Jamaica home on the morning of Dec. 10, 1976, reportedly on his way to get a haircut. Investigators determined the victim to be a regular barbershop customer of Motta, who officials said stabbed Seitz after robbing him of $7,000 to $8,000.

George Clarence Seitz was a War World I veteran.

Katz said it was the first successful usage of genetic genealogy by city prosecutors.

“No matter how much time has passed, we will use every tool at our disposal to achieve justice,” Katz said. “It is precisely for cases such as this one that I created the cold case unit when I became Queens district attorney.”

Motta, a Jamaica resident, is expected to be sentenced on Nov. 7. His attorney did not immediately respond to a request seeking comment.

“For the gruesome murder of a World War I veteran, the defendant eluded arrest for more than 46 years,” Katz said. "Now he is headed to prison thanks to the collaboration between the NYPD and our cold case unit.”