A retired U.S. Army veteran is still piecing together the disappearance of his geologist son years after he vanished from an Arizona work site, with new investigators looking to break open the four-year-long cold case using new forensic evidence. 

24-year-old Daniel Robinson vanished after leaving work at around 9 a.m. on June 23, 2021, according to the Buckeye Police Department. Daniel’s father, David Robinson, subsequently reported him missing later that day after his coworkers reached out to tell his family Daniel did not return to work. 

“When I first called in, [authorities] made me hang the phone up, wait two hours and call back,” the elder Robinson told Fox News Digital. 

The two men forged a bond through the disappearances of their children, with Petito ultimately traveling to Arizona in April of this year to help search for clues surrounding Daniel’s disappearance. 

“He called me in January and said, ‘Dave, I want to be a part of the search,” Robinson told Fox News Digital. “He said ‘I don’t want it to be about Gabby. I just want to come in as a friend to come out here to help you.’”

Petito is celebrating the resurrection of evidence in Robinson’s case, telling Fox News Digital the addition of new investigators is “fantastic.” 

“I really pray for him and his family,” Petito said. 

Robinson continues to advocate for missing Americans throughout the country, and he is pushing for new legislation to create federal standards regarding law enforcement’s response to missing-persons reports while running for a seat in South Carolina’s Second Congressional District. 

“The only thing that kept me straight is my love for my son and my military training,” Robinson said. “I had to rely on military training to look at my son as a mission, and I put the mission first.”