By Marianne Martinez, CBS 11 News

ARLINGTON (CBSDFW.COM) – A 26-year-old North Texas Marine Corps reservist was killed in action in Afghanistan last week. According to a statement issued by the United States Defense Department, Staff Sgt. Jeremy Smith of Arlington died in combat in the Helmand province of southern Afghanistan. He was a 2003 graduate of Arlington’s Martin High School.

Smith’s body is scheduled to return to North Texas on Tuesday. Upon arrival at DFW International Airport, the Marine will be honored with a water cannon salute.

But according to an article in the Fort Worth Star-Telegram, the United State Pentagon is investigating the possibility that Smith was actually killed by friendly fire. The newspaper said that U.S. Marines saw infrared images of armed men moving toward them, and sent a drone – or a remote-controlled airplane – to attack what they believed were enemy forces.

Smith’s father said that he forgives the mistake, and would rather focus on his son’s service and not how he died.

According to Martin High School counselor Susan Kingen, Smith had decided to be a Marine after the 9/11 terrorist attacks. She said that he wanted to serve his country, adding that she was proud of the man that Smith had become. “He was an awesome, inspiring young man,” Kingen said.

Smith visited Kingen two years ago to thank her for her guidance. Smith’s father called last week to tell her the news of his son’s death.

A funeral for Smith is planned for Friday at Dallas-Fort Worth National Cemetery. The Marine will receive a purple heart at graveside services.