Durham, N.C. — Donald "Donnie" Watson loved racing so much that he raced stock cars for 40 years.

In the past 10 years, he was a sponsor of a major driver.

He was also a Durham firefighter and captain for more than 33 years before retiring in 1992.

That's when he started Biggs and Watson Towing.

But to Rocky Watson, he was simply "Dad."

"He was rough around the edges, but just as soft on the inside as you could get," Rocky Watson said Thursday. "He just loved doing stuff for people – no matter what it was or who it was. As long as you were trying to do something for yourself, he would do anything for you."

Rocky Watson still doesn't know what happened to his father.

"It's a huge mystery," he said. "It makes it very difficult."

Durham police say Donnie Watson, 74, was found dead and covered in blood in his home on Regis Avenue on July 9.

Investigators are treating his death as a homicide. So far, no one has been arrested.

Beyond that, they aren't commenting about the case or a possible motive.

But Donnie Watson's brother, Wayne Watson, fears he might have been targeted.

He says that it wasn't unusual for his brother to help others with their financial problems or loan them a car.

He fears that generosity, along with carrying large amounts of cash in his wallet and wearing expensive gold jewelry, might have been a factor in the attack.

"He was just a super person, hard-headed at times, but with a heart bigger than he was," he said.

A retired Durham police officer, Wayne Watson said his brother died from multiple blunt-force injuries to the head.

"Of all the murders I went to (as a police officer), I never saw a more brutal murder than my brother's, and it hurts," Wayne Watson said. "I'm not doing good. I wake up after sleeping, maybe two hours a night, thinking of him or trying to figure out what the investigators are doing."

Donnie Watson had been at Emerald Isle with his wife in the week before his death, family members say. He returned home on July 7 and met family members at Southern National Speedway in Kenly.

On July 8, he had lunch with his son at his home.

Later that night, sources tell WRAL News, he reportedly went to a local Veterans of Foreign Wars post and then to an Internet sweepstakes café on N.C. Highway 98.

A co-worker found his body July 9 after he didn't show up for work.

"It's hard to even mourn right now, because you just don't know anything," Rocky Watson said. "All you can do is try to get back into some kind of routine."