A Yale graduate student and U.S. army veteran was shot to death in what initially appeared to be a random act of violence, shortly after proposing to his girlfriend, and the lead detective on the case recently revealed how authorities nabbed the killer and discovered an eerie obsession.

Kevin Jiang, a 26-year-old graduate student at Yale’s School of the Environment, was found dead with multiple gunshot wounds outside his car in New Haven, Connecticut on Feb. 6, 2021. 

Jiang’s death sparked a nationwide manhunt, until authorities arrested Qinxuan Pan, a longtime Massachusetts Institute of Technology researcher originally from China. 

Qinxuan Pan, accused of gunning down Yale University graduate student and U.S. Army veteran Kevin Jiang, appears in court on Tuesday, June 1, 2021. (Fox News)

At the time of his death, Jiang was a devout Christian and veteran of the U.S. Army and a National Guard reservist. He was pursuing a graduate degree at the Yale School of the Environment and was killed a week before his 27th birthday. 

“Kevin’s life was short but colorful, and brought so much joy, happiness and positivity to those around him,” his mother, Linda Liu, said at his funeral. “Although Kevin is gone from us now, Kevin is the most wonderful gift God has ever given me on Earth.”

Fox News’ Danielle Wallace contributed to this report.