Casey Owens will always be a hero to his sister.

“There is the saying that all gave some, but some gave all,” says Lezleigh Owens Kleibrink of Trophy Club. “That was Casey.”

The Marine lost both legs when his Humvee hit an anti-tank mine in Iraq in 2004. For his bravery, he received the Purple Heart.

“Casey wasn't perfect but he stepped up,” she said. “That's what makes him a hero to me."

What really hurts her is knowing that a fellow Marine stole her late Casey's story of valor. It was Casey's fellow battle buddies who discovered Brandon Blackstone's web of deception.

“It took my breath away that someone would do something like that,” she says.

Blackstone recently pled guilty to felony counts related to the deception. He will be sentenced in February. He faces up to 21 years behind bars for his crimes.

For years, Blackstone had gone around the country talking about how he had been injured when a Humvee ran over a land mine. He claimed to have suffered a traumatic brain injury. He claimed he suffered leg and ankle injuries. He claimed he earned a Purple Heart.

None of it was true.

“He may have enlisted in the Marine corps, but he's not a Marine,” Kleibrink said. “Marines don't behave like this.”

The road that led Casey to join the Marines started with the 9/11 attacks. He was in college at the time. He quit and joined the Marines. His sister says he had found his calling.

“He was very proud to serve,” Kleibrink says. “He planned on being a grunt, a lifer.”

Blackstone joined the Marines in 2004.

Blackstone and Casey Owens did serve in the same unit in Iraq. He was apparently nearby at the time of the explosion with another platoon.

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.

His sister says the explosion blew off one of his legs and badly mangled the other. He had burns all over his body. A piece of a carburetor hit his neck. He had hundreds of pieces of shrapnel in his body.

His mother and sister rushed to Germany.

“They were certain he was going to die,” Kleibrink says. “He broke everything you would possibly think of to break.”

About two weeks later, doctors amputated the other leg. Recovery was long, slow and painful.

Meanwhile, Blackstone left Iraq not long after Casey. He suffered a ruptured appendix and was taken to Germany for surgery, according to The Dallas Morning News.

He did not return to combat.

Over the years, Blackstone would make a business of out of claiming to be an injured warrior. He started a charity to raise money for other wounded veterans. In a video posted on YouTube, he claimed that because of a traumatic brain injury he suffered from seizures and terrible migraines.

“When I signed up, I basically felt like I had written the Marine Corps a blank check for the price of my life and I felt cast away,” he said.

He claimed that he had locked himself in his house and that he had post-traumatic stress disorder.

“I was diagnosed with insomnia,” he said. “I couldn’t sleep for long period of time...I ended up 100 percent disabled and unemployable due to my mental state and the injuries that I sustained.”

Blackstone even conned a wounded war charity into giving him a mortgage-free house in 2012.

“This is the coolest thing I think that’s ever happened,” he told News 8 in 2012 when he found out he was getting the house.

He falsified records to receive disability checks for almost a decade. He forged witness statements from two Marines who he claimed that seen the explosion, according to federal court documents.

It all unraveled when Blackstone, an Arlington native, made the mistake of showing a picture of the mangled Humvee to one of Casey's Marine buddies while they were attending a program that helps wounded warriors.

Blackstone claimed he had been injured in the explosion. The friend knew it was a lie because he was in the Humvee behind Casey’s.

The friend told other former Marines who had been there that day. One of them told an FBI agent who was a former Marine which kicked off the federal investigation.

“The only thing I can figure out is that he convinced himself,” Kleibrink says.

When one of Casey’s Marine friends told her what had happened, she says it “felt like someone took a baseball bat and hit me in the chest.”

“I wish I could relay to this individual the hell that we've lived through,” Kleibrink says.

An iconic photo shows Casey at George W. Bush's 2005 inauguration. He is in his uniform in a wheelchair. He is saluting during the national anthem.

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.

But the years of repeated amputations, pain and problems caused the injuries to his brain provide to be just too much. 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. The dog now lives with Casey’s mother in the Houston area.

“We just got done with Thanksgiving and all I had was an empty place at the table,” she said. “It is not a worth a single cent that this guy got. I wish I could relay that to him that he’s caused more harm than good.”

She says the men who served with her brother exhibited the true meaning of Semper Fi. They were always faithful to their fallen brother and his family.

“I just want it to be a closed case so that these guys know their Marine is OK,” she says. “He's standing at the gates of Valhalla. And he's proud of them. and they're proud of him. That's what matters most to me.”

Kleibrink and her mother will be his sentencing.

In his plea agreement, Blackstone admitted he lied to get the house and that he lied in order to be able to draw disability. His plea includes a requirement that he return the Purple Heart he falsely claimed as his own.

If Kleibrink gets the chance, she'd like to ask Blackstone why did he try to steal her brother's valor... something that was not his to take.