SAN JOSE (CBS SF) — Next month’s primary election includes a showdown in the South Bay as Santa Clara County’s longtime sheriff fights to keep her job after overseeing one of the biggest scandals in department history.

Sheriff Laurie Smith is the first female sheriff in California, but her job is in jeopardy after her jail guards were convicted in the beating death of an inmate.

In the June primary election, Smith is squaring off against four challengers including her own former second in command.

KPIX 5’s exclusive survey USA Poll shows that while Smith has a substantial lead, but a large number of voters remain undecided

They once worked side by side, but now Sheriff Laurie Smith and former Undersheriff John Hirokawa are fierce political opponents.

In the primary election for Santa Clara County Sheriff, Smith leads with 26 percent, according to our KPIX Survey USA Poll.

Next is Hirokawa with 16 percent. Former Sheriff’s Lt. Jose Salcido is running third with 11 percent.

Sheriff’s Deputy Joseph La Jeunesse and former San Jose Police Sgt. Martin Monica have three and two percent, respectively.

But a massive 43 percent of the voters polled are still undecided.

“The voters in Santa Clara County are very intelligent. They know what to look for. They’ve made the right choice in the past,” said Smith when asked about the poll numbers.

She was referring to her string of 5 previous victories…making her the longest standing sheriff in Santa Clara County history.

But this election comes after the murder of mentally ill jail inmate Michael Tyree at the hands of three of her correctional deputies, who all were convicted last year.

“What the polling tells me is that the majority of the voters want change,” said Hirokawa.

The poll also shows what issues voters most care about, including local law enforcement working with federal authorities, police use of force and jail conditions.

While Smith took credit for swift action against the deputies after the Tyree death, Hirokawa says he was the one planning jail reforms.

“If you look at the reports and the things that were done, they were based on how I was trying to funnel those changes,” said Hirokawa.

Salcido was not available on camera but told KPIX 5, “People from all parties are supporting me. The numbers are encouraging, but the most important poll will be on Election Day.”

Both challengers are hoping to make it to a November runoff, with smith hoping to get 50 percent plus one to win the race outright in June.