A small plane flown by Stephen E. Barnes, a former partner at one of the nation’s most famous personal injury law firms, crashed in upstate New York on Friday morning, killing him and a passenger, a knowledgeable attorney who said the matter.

The single-engine plane crashed in a woodland area near Pembroke, New York, about 32 miles east of Buffalo, said Kathleen Bergen, a spokeswoman for the Federal Aviation Administration.

The attorney said only two people – Mr. Barnes and his niece – were on board the plane, speaking on the condition of anonymity as he was not authorized to speak on behalf of the Barnes family. Mr. Barnes was 61 years old, and his niece Elizabeth Barnes was in her late twenties.

William A. Sheron Jr., Genesee County Police Chief, said in a statement that residents had seen the plane, which was heading east to west, landing at 11:46 am and exploding in some woods near Boyce Road. He confirmed the killing of a man and a woman, but did not immediately recognize them.

Sheriff Sherwin said the plane, a TBM 700 that can carry up to seven people, left New Hampshire around 10:18 a.m. and was supposed to land in Buffalo less than two hours later.

Nearly 30 years ago, Mr. Barnes & Ross M. Selino Jr. created Cellino & Barnes, a Buffalo personal injury law firm. They built it into a multimillion-dollar company that became a household name known with its catchy anthems on national television. It has hired more than 50 attorneys in five offices in New York state, and also has offices in California.

After their legal cases were settled in June, the former two partners were appointed to lead separate companies, though It was not clear who would get the rights To the company’s previous phone number – (800) 888-8888 – which was popular with thousands of commercials.

Mr. Barnes, who was left behind by three children, He took ownership of the company’s branch office In Buffalo and plans to rename it to Barnes Firm, his new company, in the coming weeks.

“Steve has been a friend, colleague, partner and mentor of many people across our company,” The Barnes Firm said in a statement, adding, “Steve and Elizabeth will be greatly missed by many.”

On the night of the crash, Mister Celino put aside the intensity of the recent breakup. In a statement sent to The Times, he expressed his “deep sorrow” at the death of his former colleague and Mrs. Barnes.

“He was always a fearless advocate for his clients,” wrote Mr. Celino. “His death is a great loss for the legal community.”