On Monday, Israel's police force announced that two suspects had been detained as part of an investigation into ties between the prime minister's office and Qatar. It provided no further details, citing a court-imposed gag order on the case.
Israeli media reports subsequently identified them as Yonatan Urich, a very close adviser to Netanyahu, and Eli Feldstein, a former spokesman in the prime minister's office, and said they were suspected of contact with a foreign agent, money laundering, bribery, fraud, and breach of trust.
Netanyahu later cut short an appearance at his separate trial on corruption charges, which he denies, to provide recorded testimony to police investigating the case at his office in Jerusalem.
After being questioned, Netanyahu posted a video online in which he condemned both the arrests and the wider investigation.
"I understood that it was a political investigation but I didn't realise how political it was," he said. "They are holding Jonatan Urich and Eli Feldstein as hostages, making their lives miserable over nothing."
"There is no case, there is absolutely nothing, just a political witch hunt, nothing else."
The prime minister's Likud party also issued a statement accusing the attorney general's office and the Shin Bet chief of "fabricating" the case and attempting to "terrorise Yonatan Urich in order to extract from him false testimony against the prime minister through blackmail".
On Tuesday, a judge at Rishon LeZion Magistrates' Court extended Urich and Feldstein's detention by three days, saying there were "reasonable suspicions" that required a thorough investigation. The police had requested a nine-day extension.
Judge Menahem Mizrahi said in a decision that investigators suspected that the two men had acted to "promote Qatar in a positive light" and "spread negative messages about Egypt" and its role as another mediator in the Gaza ceasefire talks.
For this purpose, the judge said, a "business and economic connection" was created between a US lobbying firm working for Qatar "through the mediation of \[Urich\] in return for monetary payments which were passed to \[Feldstein\]" through an Israeli businessman.
Last week, Israeli media published a recording in which the businessman was heard saying that he had transferred funds to Feldstein on behalf of a US lobbyist working for Qatar.
At the time, Feldstein's lawyers said the payments were "for strategic and communications services Feldstein provided to the prime minister's office, not for Qatar". They also said Feldstein was not aware of any connection between the businessman and other parties, including Qatar. Ulrich's lawyers said he denied involvement.
A police representative told Judge Mizrahi on Tuesday that Urich was also suspected of passing journalists messages from a source linked to Qatar, which were presented as if they came from senior Israeli political or security officials.
Ulrich's legal team, which includes Netanyahu's defence lawyer Amit Hadad, said they would submit a request to lift the gag order on the case to expose "the injustice done to him". The judge went on to approve the request, saying the gag order had been repeatedly violated.