(CNN) Three suspects were seen walking near the home of a California tech executive with a rifle and a duffel bag minutes before police believe he was kidnapped and later killed, newly released surveillance video shows.

The suspects are seen walking out of an alley onto the street where Tushar Atre lived, according to the video posted Wednesday by the Santa Cruz County Sheriff's Office

Atre was the founder and CEO of AtreNet , a web marketing and design company, CNN affiliate KPIX reported . He was reportedly kidnapped last month and his body was found later that day in his car.

Police hope the public will recognize the suspects caught on surveillance footage.

"We are asking for the public's help in identifying the suspects seen in the video," Santa Cruz County Sheriff's Office posted on Facebook Wednesday. "The reward has been increased to $150,000 for information leading to the arrest and conviction of the people responsible for the crimes."

Atre, 50, was last seen getting into his 2008 BMW SUV, the sheriff's office said.

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