FERNLEY, Nev. (AP) — A Navy veteran who served as an engineer on a nuclear submarine is on an even more important mission now — seeking a way to help others in the name of his little sister, who was kidnapped, killed and buried last month in northern Nevada’s high desert.

“At the end of the day, I just don’t want this to happen to any other families,” Casey Valley told The Associated Press. “I want to do everything I can to make sure no one ever has to go through any of this.”

Hundreds of townspeople turned out for a weekend celebration of the life of 18-year-old Naomi Irion at a park in rural Fernley, about 30 miles (48 kilometers) east of Reno.

The daughter of U.S. State Department workers, Irion moved there from South Africa last summer to live with her brother. She disappeared after video surveillance in a Walmart parking lot showed a man get into her car and drive them away early in the morning on March 12.

Troy E. Driver, a 41-year-old from nearby Fallon with a violent criminal history, was arrested and jailed on a kidnapping charge March 25. Driver previously served more than a decade in a California prison.

Four days after his arrest, a tip led investigators to a remote gravesite more than 60 miles (96 km) away, where Irion’s body was found in neighboring Churchill County. On Friday, Driver was arraigned in Fernley on an amended criminal complaint and ordered held without bail on first-degree murder, kidnapping, destruction of evidence and other charges.

Valley, a soft-spoken man with a bushy red beard, said he was frustrated that sheriff’s deputies didn’t act quickly enough to file a missing persons report when he first contacted them March 13.

He went the next day to the Walmart near U.S. Interstate 80 where Irion had gone to wait for a shuttle bus to take her to her job at a Panasonic plant. Signs posted in the parking lot alert shoppers “cameras in use.”

Valley knew he had to find out if there was surveillance video of his sister, so he tracked downed a store security officer.

“At first he didn’t take me seriously. But finally he said, ‘What do you want?'” Valley said. “We sat in the security office and watched the tape and became convinced it showed the suspect enter her car. I called the sheriff, and they were there in 15 or 20 minutes.”

Valley said he then spent “probably two hours” reviewing the footage with a deputy.

Prosecutors say in the amended complaint that Driver shot Irion northeast of Fernley, where he took her “for the purpose of committing sexual assault and/or purpose of killing her.” In addition to burying Irion’s body, Driver disposed of tires from his truck in an effort to eliminate incriminating evidence, according to prosecutors.

Driver’s public defender, Richard Davies, said Driver maintains his innocence.

“We are prepared to generate an aggressive defense,” he told reporters Friday. “Right now, everybody is jumping to conclusions.”

While initially critical of the investigation, Valley told reporters outside Justice Court on Friday that finding his sister’s body was “some amazing detective work.” He said the family went to the remote gravesite, which “looks like any other part of the Nevada desert.”

“It’s one drop of water in the Pacific Ocean,” he said. “It truly is a miracle that we have closure” and “Naomi is not suffering.”

“We need to take whatever peace we can get from that,” he said.

Sunday’s gathering was surrounded by ribbons in rainbow colors — Irion’s favorite — which continue to flutter from sign posts along main street just off I-80. The town was founded more than a century ago along a canal that was built as part of the U.S. West’s first irrigation project, intended to help “make the desert bloom” and attract settlers.

Valley, 42, served as a Navy submarine nuclear machinist mate stationed in Bangor, Washington, from 2009-16 and now works as a critical facilities engineer for Apple.

He has emphasized from the start Driver is a “human being” who is innocent until proven guilty. He said after the initial arrest for kidnapping he was concerned for Driver’s safety if released from jail.

Davies said prosecutors have not declared whether they will seek the death penalty but acknowledged “all options are on the table.”

For now, Irion’s family isn’t advocating for Driver’s execution, Valley said.

“We’ll see what happens,” he said, adding he knows death penalty cases can drag on with years of appeals.

“It complicates the process. That being said, it is the DA’s decision. If this guy is tried and found guilty, I just don’t want the perpetrator to be able to do this to any other person.”

Irion lived with her parents at U.S. embassies around the world growing up. When she was 13, they moved to Moscow, then Frankfurt, Germany, then South Africa, where she graduated from high school before moving last summer to Fernley.

Valley, who was 14 when his sister was born, changed her diapers and became her de facto babysitter, said family and friends already have begun work to create a scholarship in her name.

“I would like people to know Naomi would want positive change to come from this. We want to let people know this can happen to anyone,” he said.

“Naomi was my responsibility. I’m her big brother. It’s my job.”

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