BERKELEY (CBS13) — A dog walker in Berkeley made a grisly discovery last week, finding an Elk Grove teen murdered.

Seth Smith, 19, was fatally shot just before starting his third year at UC Berkeley.

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Family and friends say the Cosumnes Oaks High School graduate was vibrant, witty and smart, and often took long walks to help clear his head after a long day. But last week, his long walk took a tragic turn. 

“Somebody literally walked up to him and put a gun to the back of the head and shot him. And we don’t know why,” Seth’s mother Michelle Smith said. 

It’s the “why” and the “who” that keeps Michelle Smith up at night.

“Devastation- there will be a hole in my heart forever,” she said. 

Someone walking their dog found her son near a bus stop with a gunshot wound to the head. He was just a mile away from his new apartment in Berkeley.

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“My gut says it was either someone with some kind of maybe mental issues or it was a robbery gone wrong,” Michelle Smith said. 

The 19-year-old was set to graduate from UC Berkeley next year with a degree in history and economics. His dream was to continue his education in Europe, studying at the London School of Economics.

Seth’s high school theater teacher, Christina Chun-Moslen, says he shined on stage.

“He would have large roles and he would have small roles. It didn’t matter. He took the time to take care of everyone else,” Chun-Moslen said.

Now everyone else is trying to wrap their heads around this senseless crime that took the life of a young man with a bright and promising future.

“Seth was an amazing person. He was very kind and sweet and he did not deserve to have his life cut short,” Chun-Moslen said. 

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Police say they’re now pouring over video from security cameras in the neighborhood. The City of Berkeley is also offering a $50,000 reward for information leading to an arrest and conviction in the case.

Adrienne Moore