UCLA killer Mainak Sarkar turned violent despite foundation for success

He had a wall's worth of academic degrees from top universities and a new wife in his chosen country

With a wall's worth of academic degrees from top universities and a new wife in his chosen country, Mainak Sarkar entered mid-life with a foundation of success.

Then his life began to unravel. This week he snapped and, for reasons that investigators are still trying to understand, gunned down those he once held close.

Authorities say Sarkar killed his estranged wife in a Minneapolis suburb then drove across half the country to Los Angeles and fatally shot the UCLA professor who had helped him earn an engineering Ph.D.

As panic began to spread on the bustling University of California, Los Angeles campus, he turned the gun on himself.

He left behind devastated families, a shaken university community, a "kill list" that included the name of a second UCLA professor he felt had wronged him and many unanswered questions.

Chief among them is what led him to violence. Police have not detailed when they believe Sarkar shot Ashley Hasti after apparently breaking into the Minnesota home she shared with her father; whether he committed other crimes en route to California; or why he felt wronged by another professor on the "kill list" who was not on campus when Sarkar arrived with two semi-automatic pistols.

What soon became clear was that Sarkar believed the professor he killed, William Klug, had stolen code from him. In March, Sarkar posted online that Klug the man he had praised in his 2013 dissertation as a mentor had made him "really sick."

Colleagues said only a deranged person could conclude someone of Klug's character would defraud a student.

"Apparently he's harboured those feelings over the past three years since his graduation" but investigators hadn't found any "trigger event" that would explain why he decided to kill now, Los Angeles police Captain William Hayes said.

He did say prescription medication, possibly Valium or a similar sedative, was found in the St Paul, Minnesota apartment where Sarkar had lived.

Even before his death, Klug had been hailed as a caring father and gifted educator who inspired his students. Hundreds gathered to honour him at on-campus vigils.

Klug's outgoing personality contrasted with Sarkar's introversion.

Where Klug smiles in pictures, Sarkar rarely does. "He was a little bit of a loner," said Ajit Mal, an engineering professor who taught Sarkar in one of his earliest classes at UCLA, where he enrolled in 2006.