Then, on the morning of Oct. 18, a hitchhiker in Utah rounded a bend along a barren stretch of Interstate 70 about 47 miles outside of Green River and nearly 900 miles from Welch's home. It's a desolate area, parched beneath relentless summer sun.
"It's a pretty lonely stretch out there," Utah Highway Patrol Lt. Scott Robertson said of the region.
The hitchhiker looked down into a deep ravine. He saw a mangled, maroon Pontiac van.
Police soon arrived and found Welch's body pinned in the car.
Robertson said Welch apparently crashed into the ravine Sept. 3, just one day after leaving Kansas. No one saw it happen. He was heading west on Interstate 70 when he drove about 50 yards off the road then plummeted into an 80-foot chasm well out of view of passing cars. According to Robertson, the road curves at the spot where Welch left the pavement, indicating he may have fallen asleep at the wheel.
But Welch didn't die, at least not immediately. According to Robertson, he suffered several injuries and couldn't escape, so he passed his time writing notes to his family.
At some point, Welch died. Police are waiting for the results of a medical examiner's investigation to hopefully shed more light on Welch's death.
Robertson declined to describe the information in the notes, calling them "a pretty private matter."
Welch's wife, Kelly, offered more information on Twitter.
"Dave was entrapped in the vehicle down the 80-foot ravine, he wrote each of us a love note. He knew he was dying and there was no way out," she tweeted the day police found Welch. The tweet came just hours after Kelly announced on Twitter that students at Kansas State University, where she works, were planning a vigil for Welch. A later tweet reveals that Welch lived for "several days" after the crash.
Kelly Welch could not immediately be reached for comment Monday.
Welch's funeral took place Friday he nearly missed it because his body was accidentally sent to Atlanta, according to Kelly and his family saw his death certificate Monday.
But many of the questions surrounding Welch's death remain a mystery. Neither Robertson nor Droge knew why Welch left his home without saying anything. They didn't know where he was going or why he may have been driving through Utah.
Instead, both officers described Welch's death as "tragic" and unfortunate. The explanation for why it happened, however, may have died with Welch.