An infamous murder in Belfast gets primetime treatment in the “48 HOURS: NCIS” documentary series. The “The Sting” episode airs Tuesday, June 13, at 10 p.m. on CBS ET/PT.

In 1983, Mervin “Sonny” Grotton left work at the Naval Education Training Center in Newport, R.I., for his home in Belfast. As he walked to the front door, he was shot dead.

“There was someone hiding by the woodpile that was piled in the driveway, and for some reason they shot my dad,” said Grotton’s daughter, Rosalyn Grotton. “Things don’t happen in Belfast, Maine — but they do.”

Local police initially suspected his wife, Norma Small, but they didn’t have enough evidence to arrest her. Then the case went cold for nearly two decades … until a team of NCIS agents took another look.

“I grew up in a military family,” said retired NCIS agent Dave Truesdale, a tough, tattooed law enforcement professional with a black belt in martial arts. “Any time that I see a military member hurt by somebody, it does push me to resolve that incident.”

In this case, the agents had a hunch that Small was involved in some way. As they peeled back the layers, agents said they found out Small had a much different life when her husband was away on duty, one that involved other men. But was that enough to want her current husband dead? To get evidence, they had to risk their lives by going undercover. Small was their initial target.

“Undercover operations can be very dangerous,” said Truesdale. “You have to develop a role or persona, and once you develop that persona, you perfect it. In this undercover operation, I identified myself as Tony.”

“Tony” set up a meeting with Small. Truesdale, who said he likes going undercover because it forces him to think on his feet, also understands the risks.

“Best-case scenario, you blow your line,” Truesdale said. “Worst-case scenario — you get killed.”

The investigation would lead police to two men: Boyd Smith, the former boyfriend of Small’s daughter; and Joel Fuller. Smith and Fuller denied they were involved. In 2002, Small, Smith and Fuller went on trial for the murder of Grotton; Small was convicted and is serving a 70-year sentence. Smith and Fuller were acquitted in separate jury trials; Fuller is prison for life for two drug-related murders committed in Waldo County.

Narrated by NCIS series star Rocky Carroll, “48 Hours: NCIS” is a six-part documentary series from the award-winning team at “48 Hours” that gives viewers unprecedented access to some of the biggest cases handled by the real Naval Criminal Investigative Service. The series explores the kinds of difficult cases that have inspired CBS Entertainment’s successful primetime series “NCIS,” “NCIS: Los Angeles” and “NCIS: New Orleans.”

“The Sting” episode is produced by Alec Sirken; Paul LaRosa is the senior coordinating producer. Diana Modica, David Spungen and Marlon Disla are the editors. Josh Gelman is the supervising producer. Anthony Batson is the senior broadcast producer. Susan Zirinsky is the senior executive producer.