The death of 84-year-old South Buffalo resident Donald J. Rossel was officially declared a homicide by Buffalo police after an autopsy Wednesday by the Erie CountyMedical Examiner’s Office.

Authorities late Wednesday said the medical examiner concluded that Rossel died of strangulation and had been beaten and stabbed in his Susan Lane home earlier this week.

Rossel — who competed in ballroom dancing, eagerly performed home repairs for neighbors and found love after a heartbreaking divorce — died before his time, neighbors agree.

This is the city’s ninth homicide of the year.

There are indications that Rossel was repeatedly attacked, authorities said, adding that the fatal assault apparently was not random and that there were no signs of forced entry into the split-level home.

For Rossel’s neighbors, who described him as an indefatigable “”leprechaun,”” there was a burning question late Wednesday:

Who would want to hurt this decent human being?

“”I’ve known Mr. Rossel my whole life. I can’t call him Don. He’s Mr. Rossel to me. I grew up on this block and moved back here from West Seneca last May with my husband,”” saidNina Werner, who lives two doors away.

“”When we had flooding in the basement, Mr. Rossel was here with his plumber’s electric snake, this big machine.””

A few years ago, Rossel celebrated his 50th wedding anniversary by taking a trip to China with his then-wife, Elaine.

“”He had gotten his knees replaced before the trip, and when he came home, he told everyone he walked all

over China with his new knees,”” said Werner, who had often returned to Susan Lane to visit relatives before making the move back to the old neighborhood, which resembles suburbia more than a city setting.

Monday night, life appeared to be normal on Susan Lane, especially at Rossel’s home, according to next-door neighbor Lisa Knezevic, who kept a watchful eye out for him.

“”I was walking my dog, and the lights were on in Don’s home and the curtains open. I could see the TV was on and both vehicles were in the driveway,”” she said, though she did not see him.

Knezevic says it’s hard to believe that anyone would want to harm Rossel, whose active lifestyle reminded her of a high-powered, fit and trim leprechaun.

Twice, he suffered strokes and recovered, she said.

“”He’d show me pictures of him and his girlfriend at ballroom dance competitions at the VFW and local churches. They would get all dressed up in costumes for the competitions, and they’d win a lot of the time,”” the neighbor said.

The owner of numerous rental properties that he still personally maintained, Rossel had experienced his share of grief. After the breakup of his marriage, he told neighbors he was devastated. When his son Gary, 54, committed suicide in the basement of the home two years ago, the father openly grieved.

“”At the wake, he told me how much he missed Gary,”” Werner recalled.

The South Buffalo native, however, would not let life beat him down, neighbors agreed.

After the divorce, Rossel decided that he did not want to go through life alone.

“”He reconnected with a past love. He called a girlfriend whom he had dated before he had married, and her husband had passed away,”” Knezevic said of how Rossel found his dancing partner.

When another son, Brian, became mentally ill and was placed at Buffalo Psychiatric Center, Rossel visited him weekly, bringing him money and cigarettes, Knezevic said of her neighbor’s fatherly devotion.

Brian Rossel also visited his father’s home, including this past Monday, neighbors said.

On the question of who killed Rossel, Knezevic said that it was hard to fathom why anyone would.

The best explanation she could come up with was that “”there are a lot of sick people.””

Police Commissioner Daniel Derenda declined to comment on the investigation, saying only that “”from everything I’ve heard about him, it seemed like he had a passion for life. It’s unfortunate that he was taken before his time.””

Homicide investigators are urging anyone with information to call or text-message the department’s confidential Tip Call line at 847-2255, e-mail the information to tips@bpdny.orgor click on “”Report a Tip”” at www.bpdny.org .