JERUSALEM — A long-brewing corruption case against Israeli Prime Minister Benjamin Netanyahu  shifted to the next phase Wednesday, escalating the embattled premier’s legal peril even as he fights to retain office following last month’s deadlocked election.

The first of four pre-indictment hearings, which have been anticipated for months, convened at the Ministry of Justice on Wednesday morning, signaling the likely determination of the country’s independent attorney general to pursue charges against its longest-serving prime minister. 

The drama has Israel wondering if even Netanyahu, a legendary political lock picker, could cling to power from a defense dock. 

“The very holding of this hearing will be, I think, a watershed event,” said Amotz Asa-El, a longtime political commentator and fellow at the Shalom Hartman Institute. “I think this will finally spell the beginning of his departure.”

The investigation, which Netanyahu has dismissed as a “witch hunt,” has cast a shadow on Israeli politics for more than a year. In February, Attorney General Avichai Mandelblit announced his intention to indict Netanyahu, pending these hearings, on charges of fraud, bribery and breach of trust going back to 2011. 

In a 57-page letter, Mandelblit summarized police allegations that the prime minister and his wife, Sara, accepted more than $260,000 worth of luxury goods in exchange for political favors and that Netanyahu intervened with regulators and lawmakers on behalf of two media companies in exchange for positive coverage. 

Netanyahu has denied any wrongdoing and steadfastly refused to resign, leading to what legal experts said is unprecedented entanglement of a sitting prime minister in a criminal court proceeding. Legally, he is not obliged to step down unless convicted, and he would have a chance to appeal even then. But the previous premier to be convicted of criminal charges, Ehud Olmert in 2009, resigned his office even before being formally indicted. 

The hearings that began Wednesday represent the prime minister’s last chance to head off, or reduce, the expected charges. But legal experts say the attorney general is unlikely to change course now, meaning that indictments could land in the middle of the ongoing struggle to form a new government. The hearing adjourned after 11 hours without any official statements.

Netanyahu was not required to attend it and instead had been expected to focus on salvaging talks on a possible power-sharing agreement between his Likud party and the Blue and White party of his political rival, former army chief of staff Benny Gantz. The election last month left their parties with a similar level of support in the Knesset, or parliament, and neither close to a majority. 

Last week, Israeli President Reuven Rivlin gave Netanyahu 28 days to craft a ruling coalition, urging Likud and Blue and White to reach a compromise. Talks faltered, and as his hearing began Wednesday, Netanyahu was reportedly close to returning the mandate to the president, possibly giving Gantz a chance to try. 

Gantz pledged during his campaign that he would never serve in a governing coalition with Likud as long as a legally besieged Netanyahu led the party. Netanyahu has maintained a decade-long grip on Likud, but his court battle could soften his support among nervous party members. 

“When you combine his legal situation with his failure in the election, he has morphed from being a major asset to a major liability,” Amotz said. “They will do it softly, but nonetheless they will stab him.” 

The accusations against Netanyahu stem from three separate criminal cases. In one, investigators allege the Netanyahus accepted more than a quarter of a million dollars in jewelry, cigars and other gifts from wealthy benefactors who had official business with the government, among them the Israeli-born producer Arnon Milchan, whose credits include “Fight Club” and “Pretty Woman.”

Netanyahu is alleged to have repeatedly pressed the United States to grant Milchan a U.S. visa, while at home pressuring the Israeli finance minister to extend an income tax exemption that would benefit the producer. 

In another case, while serving as his own minister of communications, Netanyahu allegedly intervened to smooth the way for a merger sought by Shaul Elovitch, majority shareholder of Bezeq, the country’s largest telecommunications company, in exchange for favorable coverage on the popular news website Walla, also owned by Elovitch. Walla reporters and editors have described being ordered to spike stories, tweak headlines and change photographs in ways that boosted Netanyahu’s image.

Netanyahu has insisted he will not step down even if indicted, setting up a possible showdown between a defiant elected official and a legal system that prides itself on independence. 

Israeli law allows for a prime minister to remain in office while being prosecuted, permitting the Knesset to remove him after a conviction. But scholars say the law did not envision a prime minister accused of such serious malfeasance, and many predicted the courts would intervene. 

“I am of the opinion that a prime minister who is indicted on a charge of bribery cannot hold office,” said Suzie Navot, a professor of constitutional law at the Haim Striks Law School in Rishon LeZion . “If he doesn’t step down, the Supreme Court will become involved.” 

Among the theories at play: that in exchange for agreeing to step down, the president will offer Netanyahu a preemptive pardon or the attorney general will offer to reduce the charges in a plea bargain. 

But Navot said such grand bargains amount to special treatment within the legal system for VIPs, letting them avoid prison where other defendants would not. That is too high a price just to spare the nation the uncertainty and drama of a criminal prosecution, she said.

“I think a strong democracy is judged by the way it deals with very important people,” Navot said. “We have had a president in prison, a former prime minister in prison, a chief rabbi in prison. This is something Israel should be proud of.”

Ruth Eglash in Jerusalem contributed to this report.