Eighteen years ago, Attleboro High School graduate James Butler was opening an exciting new chapter in his life after moving to St. Petersburg, Fla., to take a good job with a technology company and enjoy the year-round warmth.

But tragedy struck when Butler, 25, apparently stumbled onto a burglar while returning home one night in 1991 and was fatally shot.

Police found a baseball cap and a bicycle apparently left behind by the assailant, but were never able to identify Butler's killer.

All that changed last week when advances in technology and dogged determination by a civilian cold case investigator fingered a local criminal as the perpetrator.

Alphonso Williams, described by police as a career criminal, was himself killed in a drive-by shooting in 2007. Butler's mother Byrl Butler, who now lives in Englewood, Fla., with her husband John, where they deal real estate, said the announcement by the St. Petersburg Police Department brings closure to years of suffering by her family.

"We're so grateful that justice was served and that my husband and I will not have to go through a trial," Butler said.

Butler said her son, a tool and die maker and machinist, was recruited to work for a Florida company and had moved there about a year before he was killed. He rented a house there owned by his grandparents, and roomed with his cousin.

"It was really the best year of his life," Butler said. "He was easygoing and he loved golfing and beaching."

On July 16, 1991, Butler said James was returning home at night when he apparently ran into Williams, and they fought.

The killer left behind a Miami Hurricanes ballcap and a bicycle, from which police were able to collect fingerprints. But at the time, technology was not advanced enough to allow detectives to make a positive identification.

But last July, Brenda Stevenson, a civilian investigator with the St. Petersburg police, resubmitted the cap to a Florida Department of Law Enforcement crime lab. New technology allowed investigators to create a complete DNA profile from slight scrapings removed from the cap.

The DNA evidence, together with fingerprints, was enough to identify Williams as the murderer, a police department spokesman said.

Williams apparently met his end two years ago in an apparent drug-related murder.

The young Butler, an Eagle Scout, graduated from Attleboro High School in 1985 and attended Community College of Rhode Island and Wentworth Institute of Technology. He worked for Valentine Tool and Stamping company before being recruited by Sun Micro-Stamping of Largo, Fla.

Besides his parents, Butler is survived by his brothers, Dennis of Rehoboth and Kevin of Maine; and his sister, Lynn, of Northport, Fla.