OAKLAND, Calif. — As little as two years ago, Oakland seemed to have escaped its reputation as the troubled sibling of its more glamorous sister, San Francisco. Guidebooks and media outlets eagerly described the Oakland Renaissance, in which eight-course tasting menus at the Michelin-star-rated Commis restaurant attracted international jet-setters, and housewives from Marin County wheeled Peg Perego strollers alongside artists with body piercings at the popular First Friday art exhibits downtown. Just the other week, Uber, the ride-sharing service, agreed to transform one of the city’s barren department stores into a gleaming technology beacon.

Oakland, it appeared, had finally arrived.

But the death of Antonio Ramos, 27, who was gunned down before lunch on Tuesday while painting a community peace mural, was a reminder of the stubborn grit and crime that still cling to the city despite the gentrification boom that has fueled its reputation as Brooklyn by the Bay. As of Friday, the killer, who walked away from the shooting, had yet to be found.

“This senseless tragedy is one more wake-up call,” said Dan Kalb, a city councilman who attended a vigil Wednesday in West Oakland under Interstate 580, where Mr. Ramos was shot. “We have to do more to reduce the violence and get guns off the street so we’ll all be safe and can invest in the kind of things that will make this city great.”

The murder rate in Oakland was up 30 percent for the first nine months of 2015, to 65 deaths from 50 in the same period last year, according to the Oakland Police Department. This was after murders in Oakland fell from 126 in 2012 to 80 in 2014, according to police statistics. Robberies and burglaries have been on the decline as well.