A man from Maine who fatally shot his fiancee on the day before they were to be married in Florida last year will not be charged.

A grand jury decided last week not to indict John Tabbutt, 63, on a manslaughter charge in the death of Nancy Dinsmore, 62, a Portland High School graduate. The charge was recommended by police in Winter Springs, Fla.

“We are not in agreement with the grand jury’s decision,” said Dinsmore’s younger sister, Mary Guiseley of Raymond. “We don’t feel the investigation was done properly.”

Guiseley said Thursday that her family is discussing the possibility of hiring a private investigator for an independent review of what led to Dinsmore’s death in October.

“The forensics show that (Tabbutt) was four feet away from Nancy when he shot her in the heart,” Guiseley said. “People can’t figure out what happened.”

Winter Springs Police Chief Kevin Brunelle said in a telephone interview this week that his chief investigator, Detective Rob Cable, was unable to find evidence that Dinsmore’s death was premeditated. But State Attorney James Carter did concur with police that there was enough evidence to convict Tabbutt of manslaughter, based on what Brunelle characterized as negligence.

Brunelle said Tabbutt failed to identify his target properly and did not check to see whether Dinsmore was in bed with him.

“We felt there was enough culpable negligence to warrant charges,” Brunelle said. “But the jury apparently didn’t feel it rose to the level of manslaughter.”

Police said Dinsmore was shot and killed by Tabbutt on Oct. 9 in their home in Winter Springs after he mistook her for an intruder.

Tabbutt shot her in the chest with a .38-caliber handgun in a hallway about 2:30 a.m. The couple, who were living together, were to be married the next day.

Brunelle said Tabbutt told investigators that he didn’t call out to the intruder, and indicated that he thought Dinsmore “was in bed with him.”

Brunelle said Tabbutt cooperated with police throughout the investigation.

“There was no evidence of premeditation, either through the forensic evidence or the mountain of paperwork we looked through,” Brunelle said.

Dinsmore was born in Paterson, N.J., and moved to Maine and attended Maine schools. She worked for AT&T in Maine and Florida before retiring from Bell South in Florida.

A daughter, Arlene Dinsmore, who moved to Florida from Maine a few months ago, said her mother graduated from Portland High in 1965.

Dinsmore has two brothers and one sister, all of whom live in Maine.

Guiseley said her sister met Tabbutt in 2007 on Match.com, an Internet dating service, a few months after her first husband, Stephen, and her mother died.

Tabbutt graduated from Morse High School in 1965, according to a former classmate and high school friend, Roger Therriault.

Therriault, who is a lawyer in Bath, said he has not seen Tabbutt in more than 40 years. But he said, “He was well liked in our class. He had a lot of friends.”

Guiseley said a couple of major television networks have contacted the family about doing a story, but the family has not reached any decisions. “We’re just trying to regroup.”

Staff Writer Dennis Hoey can be contacted at 791-6365 or at:

dhoey@pressherald.com