Donatila O’Mahony, 43, of Central Islip, who was convicted of murder in the homicide of Lee Pederson, 69, of Aquebogue, was sentenced March 2. Photo: Suffolk County District Attorney handout

The woman convicted of murder in the killing of an Aquebogue man in March 2020 was sentenced today to 25 years to life in prison and an additional 4 and 2/3 to 14 years imprisonment in connection with possession of the murder victim’s forged will.

Donatila O’Mahony, 43, of Central Islip was convicted of murder in January after a jury trial before Supreme Court Justice Timothy Mazzei in the March 2020 homicide of Lee Peterson, 69.

Peterson was found dead in his Aquebogue home on March 8, 2020 with a single gunshot wound to the back of his head. Police determined several items, including Pedersen’s phone, car keys and cash, were missing from his home.

Prior to the murder, in 2019, O’Mahony asked a friend in New Jersey to purchase a Sig Sauer 9mm handgun, which she would later use to kill Pedersen, prosecutors said.

On the night of the murder, she borrowed that same friend’s car, which was captured on video surveillance in the area of Pedersen’s home. That car was also captured on video surveillance returning to O’Mahony’s home several hours after the murder.

When O’Mahony later returned to her own home, she asked her friend from New Jersey to dispose of several items, including the Sig Sauer 9mm handgun he had purchased for her, ammunition, and clothes, according to a press release issued by the Suffolk County District Attorney today.

O’Mahony’s friend destroyed the handgun and disposed of the clothes, but kept the plastic bag of ammunition in his home in New Jersey. The bag of ammunition was subsequently recovered by police and swabbed for DNA. The Suffolk County Crime Laboratory then conducted a forensic analysis which revealed the the presence of both O’Mahony’s and Pedersen’s DNA on the swabs, the DA’s office said in the press release.

O’Mahony was also found in possession of a will that was forged to appear that Pedersen had willed his home to O’Mahony. During the police investigation, Pedersen’s authentic will was recovered, which did not state O’Mahony was to inherit one of Pedersen’s properties as stated in the forged will.

O’Mahony was convicted by a jury Jan. 24 of the crimes of Murder in the Second Degree, a Class A felony, Criminal Possession of a Forged Instrument in the Second Degree, a Class D felony, and Attempted Grand Larceny in the Second Degree, a Class D felony.

The prison terms imposed for the Criminal Possession of a Forged Instrument in the Second Degree charge and the Attempted Grand Larceny charge will run concurrently with each other, but consecutive to the prison term imposed for the Murder in the Second Degree charge.

“This was a cold-blooded killing fueled by greed, treachery, and the complete disregard for Lee Pedersen’s life, all in order to steal the victim’s home,” said District Attorney Ray Tierney. “The only new home this defendant will be living in as a result of her actions, is prison.”

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Denise is a veteran local reporter, editor, attorney and former Riverhead Town councilwoman. Her work has been recognized with numerous awards, including investigative reporting and writer of the year awards from the N.Y. Press Association. She is a founder, owner and co-publisher of this website.Email Denise.