(NBC News) — On Thursday’s all-new “Dateline,” a small town in the Ohio River Valley is left in shock after beloved local coal miner Brad McGarry is found fatally shot in the basement of his home.

As investigators dig into his personal life, a secret affair reveals a surprising suspect.

Here is a preview of Dennis Murphy’s report:

The Ohio River Valley, for decades here, generations of men have gone underground. And in places like Bellaire, Ohio, population 4,000, it’s still a way of life.

DENNIS MURPHY: Is it as tough as most people think —

FRANCO PINACCHIO: It is.

DENNIS MURPHY:  — to be a coal miner?

FRANCO PINACCHIO: It’s not for everybody. Super physical, uh, demanding. You’re almost 2,000 feet underground. One way out. The gases will kill you. The moving equipment will kill you, the coal falling will kill you. It’s an unforgiving environment.

But with risk comes reward. In this case a big payday, for some, up to six figures, luring men like Brad McGarry to don a hard hat and take their chances underground.

The 43-year-old rose through the ranks to become a foreman. A bit remarkable because Brad McGarry was not your father’s coal miner.

DENNIS MURPHY: He was openly gay?

MELANIE ROSKOVICH: Yes.

DENNIS MURPHY: Never tried to conceal it, right?

MELANIE ROSKOVICH: Correct.

DENNIS MURPHY: Was comfortable in his skin?

MELANIE ROSKOVICH: Yes.

DENNIS MURPHY: He was being Brad.

MELANIE ROSKOVICH: Yes. He was real. He never pretended to be anyone that he wasn’t.

But Brad was also a person with a secret. And a secret, as we all know, can be dangerous.

Watch “Dateline: Dangerous Secret,” Thursday at 10 p.m. on NBC4.