A stretch of the highway near Bailey Road is where the 20-year-old was shot and killed. It happened Saturday around 3:30 p.m. After the shooting the highway was closed for about six hours. It didn't reopen until around 9 p.m.
"He had big dreams, he had a huge personality, and was so funny," said the restaurant owner's daughter, Esther Aradottir.
Tomas Mendez shooting death leaves fellow restaurant workers in shock. Was killed on Hwy 4 Saturday by another driver pic.twitter.com/GCGXoQCUk0— Vic Lee (@vicleeabc7) June 22, 2015
Mendez worked at Katy's Korner Restaurant in San Ramon. Next to the register is a picture of him on a donation bucket. It's the last photo of him taken just before he was killed.
The victim had just celebrated his father's birthday on Saturday afternoon when the restaurant closed.
"They had cakes and presents and they all sang for his dad,"
His father, Jose, has been the head cook there for 16 years. Owner Ari Georgsson says that as a child, Mendez would come to work with his father.
"Wanted to help out, cook potatoes, clean strawberries, what have you," he said. "And just wanted to be like dad, be in the kitchen, and learn the cooking."
When Mendez grew up he was hired as a cook, working alongside his dad. The young man adored him and even commuted with him. But on Saturday, Mendez drove his own car.
"Usually Tomas drove home with his dad, they usually drove in and back together," said owner Benedikta Gisladottir. "But that day, Jose had to go and see his father, so they drove in different cars. So you know."
Just before he left, Mendez ordered hot chocolate to bring to his 2-year-old daughter.
"He used to always bring her hot chocolate," said Aradottir. "When he was leaving he would get a to-go hot chocolate and bring it home to his baby."
Mendez never made it home to his baby, nor to his longtime girlfriend.
He died on Highway 4 when someone in another car opened fire, causing his vehicle to crash into the center divide. He died the day before Father's Day.
Gisladottir's son Anton Axelsson, a manager at Katy's Kreek in Walnut Creek, said his family set up a GoFundMe campaign to raise money to cover funeral costs, with the remaining funds going to Mendez's daughter.
"He cherished them and spoke of being a father, the love children bring to your heart and how he wanted to be the best father to them, provide for them and be there to comfort them as they grow," the GoFundMe page reads.
Authorities have not yet released a possible motive for the shooting and sheriff's spokesman Jimmy Lee said no suspects had been identified as of Monday morning.
For more information on the GoFundMe campaign, click here.
Anyone with information about the shooting is encouraged to call the Contra Costa County Sheriff's Office at (925) 646-2441. Tips can be emailed to tipsso.cccounty.us or can by left anonymously by calling (866) 846-3592.
Bay City News contributed to this report.