Charlotte, N.C. — A North Carolina native was among the Marines killed Monday when two U.S. Marine helicopters – one UH-1 and an AH-1 Cobra – collided in flight before sunrise over the southern province of Helmand in Afghanistan, military officials said.

Captain David “Seth” Mitchell, 30, was born in Charlotte and attended Garner High School. He later graduated from Loveland High School in Loveland, Ohio. He lived in Cincinnati for 10 years.

Mitchell was one of four Marines killed in the crash. Two others were injured.

In a separate incident Monday, a U.S. military helicopter crashed while returning from the scene of a firefight with suspected Taliban drug traffickers in western Afghanistan, killing 10 Americans including three DEA agents.

The incidents combined to make Monday the deadliest day for U.S. forces in Afghanistan in more than four years.