This is a story of honor, of stolen valor, and making sure no one steals what is not theirs.

“Honor is everything to a Marine,” says Andrew Van Wey, a former Marine.

Van Wey's fellow Marine, Casey Owens, lost both legs when his Humvee hit an anti-tank mine in Iraq in 2004.

So when he found out another former Marine named Brandon Blackstone was falsely claiming to have been injured in that explosion, it was not something Van Wey could let pass.

“I consider it just one of the grossest forms of cowardice,” he says. “His mistake was to steal a story of another Marine in a branch of service that’s known to be the smallest. A lot of people know each other and it was really what got him caught.”

Blackstone, an Arlington native, was sentenced last week to 21 months in prison for fraud and falsely claiming to have received a Purple Heart. He was also ordered to repay more than $320,000 in disability benefits that he fraudulently received.

“Marines are honorable,” says Owens’ sister, Lezleigh Kleibrink of Trophy Club. “They have a code of honor they live by. This man is not a Marine.”

Her brother was not there to see his sentencing. He killed himself in 2014.

Blackstone’s web of deception unraveled after he showed a picture of the mangled Humvee to another Marine. The former Marine knew it was a lie because he was in the Humvee behind Owens.

He told Van Wey what Blackstone was claiming.

On that awful day, Casey’s unit had gone out to rescue a fellow soldier who had been hit by a sniper. Casey was on the passenger side of the Humvee when it ran over a double-stacked IED. The explosion threw Casey about 30 feet.

“I thought he was dead when I got to him,” Van Wey says. ‘”I didn't even recognize him physically.”

For Blackstone to appropriate Owens’ story was beyond galling. It required action.

Van Wey began putting the pieces together of Blackstone’s lies.

He soon found out that charities had given him a car and a mortgage free house based upon his story.

Van Wey took the information he had gathered and met with a FBI agent.

“I told the agent I know this isn’t the crime of the century to you guys, but this has a really deep meaning for us and I hope you guys put all of the efforts and resources into this,” he says. “The guy tells me, ‘I was in the Marine Corps infantry, too.’ He was in Iraq when I was there. ‘Don’t worry, we’re going to take care of this and they did.’”

For years, Blackstone had traveled around the country telling his concocted story. He claimed to have suffered a traumatic brain injury. He claimed he suffered leg and ankle injuries. He claimed he earned a Purple Heart.

Blackstone even conned a Wounded Warrior charity into giving him a mortgage-free house in 2012.

He falsified records to receive disability checks for almost a decade. He’d gotten disability by forging witness statements from two Marines where he claimed they had seen the explosion.

“There’s something not right with this guy,” Van Wey says. “He went around the country being a motivational speaker for his harrowing tale which was all complete crap. If he had just kept to himself, he might not have been caught.”

The truth was that Blackstone left Iraq not long after Owens. He had a medical issue and never returned to combat.

For the stolen valor conviction, Blackstone received 12 months in prison – the maximum allowed by federal law. It will run concurrent with the 21 months he received for fraud.

Owens’ sister says 12 months for a stolen valor is just not enough and she’s vowing to push for a change in the law.

“It felt like a gut punch,” she says. “It felt like it was a slap on the hand. This is cheapening everything that my brother did.”

She says Blackstone never apologized. His father and wife both testified at his sentencing, begging the judge for leniency. Kleinbrink was not given the opportunity.

Van Wey recalls Owens as the “quintessential Marine.”

“He was always looking for the next fight or the next challenge,” he says.

He says Owens would have felt betrayed, angry and disappointed that someone who had once called themselves a Marine could have done something so dishonorable.

“I think he was sorry he was caught,” Van Wey says. “I don’t think he was worried for what he did.”

Casey fought hard to live. He battled the VA system, who his sister says did not give him the care that he deserved. He moved to Aspen. He competed as a Paraolympic skier.

Years of repeated amputations, pain and problems caused by the injuries to his brain proved too much and he killed himself in 2014.

“Casey lived in hell for 10 years,” his sister says. “He didn’t sleep. He was trapped within his own body, trapped with no legs and trapped with a brain that didn’t work properly anymore.”

Casey’s beloved service dog Harold was with him at the end.

Kleinbrick was there on Wednesday at the Dallas Fort-Forth National Cemetery as 20 indigent veterans were laid to rest. About a dozen of them were buried without investigators being able to find any next of kin.

While she was there, she visited the grave of one of her brother’s fellow soldiers.

“Casey’s gone,” Kleinbrink says. “So many others are gone. It was very hard to take into account another loss. Another loss that I mourn.”

She is grateful to Van Wey and Casey's other battle buddies for making sure Blackstone did not go unpunished for his misdeeds.

Kleinbrink knows what Casey would say.

“He would say hurrah,” she says. “He would say thank you. He would say I know you had my six.”