It has been a trying year for San Francisco's flamboyant 58-year-old mayor Joseph Alioto. His wife went AWOL for three weeks, the city's sanitation and transport workers called a strike, the SLA-perpetrated Hearst kidnapping in nearby Berkeley has generated a wave of bad publicity for the whole area, and worst of all by far, the Zebra killings have cast a pall of real terror over the streets of his city.

Since November there have been 18 shootings, all without warning or any obvious motive, 12 of them fatal. All of the victims were white and all of the alleged assailants black. The murders have been called the Zebra killings—no racial connotations, only the radio code used by the police in their dragnet. Working from descriptions provided by two wounded survivors, hundreds of city police began a search for a thin-faced black man between 20 and 30 years old. Several hundred who vaguely resembled this description were stopped and questioned, causing a burst of anger in the city's black community. The wantonness of the Zebra murders was little disputed, but the legality of the extraordinary stop-and-search technique—and particularly the clumsy manner in which it was publicly announced—came under serious question. Outside Alioto's mansion bitter demonstrations erupted. But inside the ornate home, with its red and gold wallpapered living room and cut-glass chandeliers, Alioto seemed genuinely surprised by the uproar.

He is an underdog candidate for governor this fall and knows he must carry black districts to win. He has enjoyed strong support in the city's black community, and he is not without influential backers this time. But he has been badly served, at least verbally, by his police chief Donald Scott. "We are not going to stop every young black," the chief said at a televised news conference. "Or big fat blacks. We are not going to stop seven-foot blacks or four-foot blacks." This astonishing phrasing on Scott's part has led some to question Alioto about his top cop's sensitivity to racial matters. "You mean it sounds like Agnew's 'fat Jap?' " Alioto asks. "I was there and I didn't hear it that way. He was simply saying they wouldn't stop a hefty black. It wasn't an insidious remark. Scott is not a press relations kind of chief. He's a policeman's policeman. People are so sensitive about language these days."

Alioto believes strongly that the dragnet is "not a racial issue." He called a press conference, he says, "not to reassure the white community we were doing something, but to ask the black community to cooperate." Denying that the police are violating anyone's rights, Alioto cites the comparable 1969 search for the city's white Zodiac killer, who has also not been caught. "With Zodiac," he says, "we stopped about 1,000 white men. I wish somebody would look into how many whites we stopped for Zodiac."

The Zebra uproar has made a shambles of Alioto's campaign. He cancelled some appearances and sent his wife to sub for him at others. Every two hours he gets a report on the dragnet, even if he's out of town. "I'm a fellow who likes to solve problems, rather than debate them," he says. Only rarely does he have time these days to unpack the violin he gets so much pleasure in playing as accompaniment to records of symphonies and operas.

Despite the present unease in the city, Alioto says, "I think the tensions this time are a lot less than they were in 1968-69 when everyone was afraid of race riots. In those days I slept with a red phone under the bed, a direct line to the police chief. People have forgotten how tense that was."