Westport (AP) — The grandfather of a Connecticut native says his grandson was one of the seven Marines killed in a training exercise explosion in Nevada this week.

Jerome Muchnick of Philadelphia told The Associated Press on Wednesday that his grandson, 23-year-old Roger Muchnick, grew up in Westport and was a graduate of Staples High School. He says his grandson served in Afghanistan and was thinking about going to college after the Marines.

He says Roger Muchnick's father and mother moved out of Westport a few years ago to North Carolina and Florida, respectively.

Jerome Muchnick says his grandson was a vibrant, loving man and he's devastated by his death.

Funeral services haven't been announced.

The Marines killed on Monday night were based at Camp Lejeune, N.C. The explosion's cause remains under investigation.