When Tushar Atre was abducted in the predawn hours of October 1, 2019, from his home perched on the oceanside cliffs in Santa Cruz, California, his friends and neighbors in the usually quiet surf community were in disbelief. Confusion over who would kidnap the successful tech executive and cannabis entrepreneur turned to fear after he was found dead hours later on one of his cannabis properties — having sustained stab wounds and a fatal gunshot wound to the back of the head.

"Everyone was spooked. You could really see the fear in people's eyes," says CBS San Francisco, KPIX reporter Maria Cid Medina.

Investigators with the Santa Cruz County Sheriff's Office cast a wide net for suspects, but according to Cid Medina, they initially did not have much to go on. "48 Hours" contributor Tracy Smith explores the ensuing seven-month long investigation in "Who Shot the Tech Exec?" 

"There were not immediate suspects," says Cid Medina. "You got a sense that investigators did not have any leads in this case.

That all changed when detectives began to dig deeper into Atre's cannabis business. As they interviewed his employees and associates, there were two names they heard more than once.

"Two of the names that kept popping up were Stephen Lindsay and Kaleb Charters," says former police chief and "48 Hours" consultant Steve Cercone.

Both men had worked for Atre in August of 2019 on one of his cannabis properties — doing mostly manual labor putting up fence posts and planting. Investigators interviewed both men in December 2019, two months after Atre's murder and learned they'd only worked for him for less than two weeks. But in that short period of time there was a lot of animosity. Lindsay and Charters apparently lost a set of Atre's car keys, and then they learned he had stopped payment on their paychecks. Lindsay admitted to investigators he was so upset he wanted to fight Tushar. There was also a story that detectives later learned surrounding a unique form of punishment Atre allegedly inflicted on the men.

"Apparently, he'd made them do push-ups … in front of other people," says Cercone. "If that were the case, they were most likely humiliated."

The keys were found and Atre eventually did pay Lindsay and Charters for their work, though only partially. They told investigators their dispute with him was resolved, and that they never returned to Santa Cruz after they stopped working for him. But five months after their interviews, they — along with Kaleb's brother, Kurtis Charters, and a friend, Joshua Camps, were arrested for Atre's kidnapping and murder. Investigators said it was a robbery gone wrong, but Mary Fulginiti, a former federal prosecutor and "48 Hours" consultant, says there's more to the motive and suggests they need to look no further than how Atre allegedly treated Lindsay and Charters.

"Does this story of Tushar humiliating Stephen Lindsay and Kaleb Charters point to motive?" Tracy Smith asked her.

"Yes," replied Fulginiti. "Definitely."

She says the fact that both men were in the U.S. Army Reserve might also play into lingering resentment.

"When you look at the Army Reserve, right, and you look at the Army or any of the military operations, I mean, they're taught respect," says Fulginiti. "And here he is feeding into that disrespect … and mistreatment."

The four men charged with the murder of Tushar Atre were all found guilty in separate trials. They were sentenced to life in prison without the possibility of parole.