A bucolic park where people, but not dogs, can roam free was the scene for years of skirmishes between two of its patrons that ended last year with one of their deaths.

But whether Charles Martin Coats, 57, of Stone Mountain stabbed William Scott Carr, 50, of Snellville last year to defend himself or was motivated by anti-gay sentiments is yet to be determined.

Opening statements Wednesday in the Gwinnett County Superior Court case that has Coats facing a life sentence for murder offered those opposing arguments. It centers on Carr's dogs, which Coats continually said he wanted leashed.

"Get your blankety-blank dogs on a leash!" Coats told Carr on one occasion, said prosecuting attorney David Keeton. The two traded insults, with Carr telling Coats to "mind his own business." Carr and his male partner were nervous about Coats, and kept a copy of a police report filed over one of their tiffs in their vehicle's glove compartment should there be another run-in at Gwinnett's Yellow River Park where paths occasionally crossed.

On the day of the stabbing, one strike to Carr's throat — "the blade went to the bone, and it got the job done" — indicated Coats' muderous intention, Keeton said.

Keeton suggested Coats was motivated by homophobia, citing testimony by one of Coats' jailmates. He did not argue the case as a hate crime, however, which, according to his assisting attorney on the case, carries no additional punishment. But Coats' bias helps explain "why he so grossly overreacted in his response to what should have been a minor situation," Keeton told the newly elected jury. "He not only resented Scott Carr's unleashed dogs." He also "resented what he thought was Mr. Carr's unleashed lifestyle."

Coats' attorney Brian Steel rejected Keeton's homophobia argument, saying the allegation comes from a convict looking to cut a deal.

Steel portrayed Coats as a simple man, a woodworker, who looked forward to daily outings at the park where he'd carry his four-inch blade for whittling. Upon first seeing Carr's unleashed dogs in 2003, Coats' politely noted they could pose a danger to patrons.

But Carr was menacing in response: "Don't you tell me what to do with my dogs," Steel related. On a second occasion, Carr met Coats' well-meaning request with a finger in his face and a threat: "I'll kick your ass. Leave me alone" according to Steel.

On the third exchange, after Carr's unleashed dogs led Coats to crash his bike, Carr pushed Coats, Steel said. Coats reported the incident — and Carr's license plate — to police. Later, Coats noticed Carr's truck patrolling his home, frightening him, Steel said.

But it was quiet between the men for nearly three years, until that fatal day on January 3 when Coats shooed away one of Carr's dogs, offending his owner. At 5 feet 11 and 185 fit pounds, Carr outmuscled a 5 feet 4, 185-pound Coats, Steel said. They threatened each other. Carr said he'd kill him, and Coats believed he was fighting for his life, Steel said.