A Navy SEAL has died after an off-duty skydiving accident while on leave in California, the San Diego Union Tribune reports.

Navy SEAL Cmdr. Seth Anthony Stone, 41, of Houston, Texas, died after his parachute failed to open following a jump from a hot air balloon. The Federal Aviation Administration is investigating the incident.

Stone, who was most recently stationed with the Hawaii-based Special Operations Command Pacific, was twice awarded the Silver Star, the Navy’s third highest award for valor.

A SEAL operator for most of his 18-year Navy career, Stone completed multiple tours to Iraq and Afghanistan.

A 1999 Naval Academy graduate Stone first spent two years as a Surface Warfare Operator onboard the guided-missile cruiser Gettysburg before being accepted into the SEAL community for training in February, 2002.

In a community where much of the work is out of the public eye, Stone gained some public notoriety in 2006, when the then-lieutenant was the commander of Delta Platoon, SEAL Team Three.

Under his command that day was Master-at-Arms Second Class (SEAL) Michael Monsoor, who was posthumously awarded the Medal of Honor after being mortally wounded on Sept. 29, 2006, in Ramadi, Iraq. Monsoor jumped on an enemy grenade that was thrown in the vicinity of his teammates, absorbing the blast with his body.

“He recognized immediately the threat, yelled ‘grenade’ and due to the fact that two other SEAL snipers, our brothers, could not possibly escape the blast, he chose to smother it with his body, absorbed the impact and lost his life in the process,” Stone told reporters in 2008.

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But Monsoor wasn’t the only hero that day. Stone was awarded the Silver Star for his actions as the leader of the unit. Reports say that Stone was on a adjacent rooftop with another sniper element when the unit came under heavy fire.

“As ground force commander for a combined sniper overwatch tasked with protecting the western flank of a battalion clearance operation, enemy insurgents attacked one of Lieutenant Stone’s elements with small arms, rockets, and finally a hand grenade that wounded three of the four SEALs in the element, one of them mortally wounded,” his Silver Star citation reads.

“Realizing the severity of the situation and the vulnerability of the embattled element, he led his team into the fray as they departed their overwatch position and moved into the street where they fought their way through heavy enemy fire toward the element in peril. Upon reaching the wounded SEALs, Lieutenant Stone took control and directed the evacuation of the wounded men.”

For additional actions, Stone would later be awarded a second Silver Star, a Bronze Star with Combat “V” Device, the Navy Marine Corps Commendation Medal, Navy Marine Corps Achievement Medal and the Army Commendation Medal with “Valor” Device.

Stone was “liked by everyone fortunate enough to cross his path. He made great friendships and found solace in pursuing his passion for surfing and other adventurous activities,” an Oct. 2 Naval Special Warfare Command blog entry read.

Along with the blog post, the Naval Special Warfare Command’s commander, Rear Adm. Tim Szymanski, offered his thoughts.

“The Naval Special Warfare community is deeply saddened and mourns the tragic loss of one of our best,” Szymanski said. “Seth’s absence will be sorely felt across the staff, command and the entire special operations community. NSW is a close-knit family and our primary focus is to provide care and support for Cmdr. Stone’s family.”