Rylee McCollum, a 20-year-old 2019 graduate of Jackson, Wyoming’s Jackson Hole High School, has been identified as one of the U.S. servicemembers killed in Thursday’s suicide bombing at the Hamid Karzai International Airport, where U.S. evacuation efforts were underway.

According to reports, this was McCollum’s first deployment to Afghanistan. He “was reportedly manning a checkpoint at the airport when the bomb went off,” according to the Star Tribune. His older sister, Roice McCollum, said her brother always wanted to be a Marine.

“He wanted to be a Marine his whole life and carried around his rifle in his diapers and cowboy boots,” she said. “He was determined to be in infantry… Rylee wanted to be a history teacher and a wrestling coach when he finished serving his country.”

“He’s a tough, kind, loving kid who made an impact on everyone he met. His joke and wit brought so much joy,” she continued.

“Rylee will always be a hero not just for the ultimate sacrifice he made for our country, but for the way he impacted every life around him for the better. Making us stronger, kinder, teaching us to love deeper,” she added.

She also said her brother was expecting a baby in mere weeks.

One week ago, Roice shared a tribute to her brother as tensions worsened in Afghanistan.

“Some people spend an entire lifetime wondering if they made a difference in the world. But, the Marines don’t have that problem. Stay safe Rylee. We love you and you have a little peanut to come home to,” she wrote, offering a prayer for members of the military fighting to protect freedom across the globe:

Dear Lord, We honor our veterans, worthy men and women who give their best when they are called upon to serve and protect their country. Bless them, Lord, for their unselfish service in the continual struggle to preserve our freedoms, our safety, and our country’s heritage, for all of us. Bless them abundantly for the hardships they faced, for the sacrifices they made for their many different contributions to America’s victories over tyranny and oppression. In Jesus’ name we pray. Amen.

Wyoming Schools Superintendent Jillian Balow also released a statement on the young Marine’s tragic passing.

 “Saying that I am grateful for Rylee’s service to our country does not begin to encapsulate the grief and sadness I feel today as a mother and as an American,” she said. “My heart and prayers are with Rylee’s family, friends, and the entire Jackson community.”

“We will find many ways to honor Rylee for this ultimate and untimely sacrifice in the coming months and years – but for now, my arms are wrapped around Rylee’s loved ones from afar and I pray they find some comfort,” she added.

Wyoming Gov. Mark Gordon (R) also spoke out after the news surfaced of McCollum’s untimely passing.

“I’m devastated to learn Wyoming lost one of our own in yesterday’s terrorist attack in Kabul. Our thoughts and prayers are with the family and friends of Rylee McCollum of Bondurant,” he said. “Jennie and I, along with all of Wyoming and the entire country thank Rylee for his service”:

As a result, the governor decreed all American and state flags will be flown at half-staff in his honor.

Twelve other U.S. troops were killed in Thursday’s blast, marking the largest single-day loss of life for U.S. servicemen since August 6, 2011, after the Taliban shot down a CH-47 Chinook helicopter carrying 30 American servicemen.