Police told Netanyahu that he was being questioned within the context of an ongoing corruption probe involving the Bezeq telecommunication company.
According to reports, legal complications for Netanyahu are mounting by the day, with four cases under investigation and others to come.
On February 13 Israeli police recommended Netanyahu be indicted for bribery, fraud and breach of public trust in two cases known as 1000 and 2000.
Mr Netanyahu has repeatedly denied any wrongdoing and has dismissed the accusations as a witch hunt orchestrated by a hostile media.
The company has denied wrongdoing. Police have yet to make a recommendation about charges in the case.
A Reuters cameraman saw a vehicle carrying two police officers pull to the prime minister's official home on Friday morning.
Netanyahu will visit Washington to meet with US President Donald Trump, and he will also deliver a keynote address at the annual AIPAC Policy Conference, which officially begins Saturday night. The lawyer said Sara was questioned under police caution, indicating that she could become a suspect.
His wife is thought to have also applied pressure on media mogul's wives to convince them to change their organisations' reporting.
Elovitch is also a suspect in Case 4000.
Filber, a Netanyahu ally for more than 20 years and a former communications ministry director general, is expected be a state witness in exchange for avoiding jail.
There were a few dozen protesters, singing songs and banging plastic pipes on garbage cans.
Some drivers touted their horns in support as they drove by. The final decision on both cases could take months. Police, however, confirmed that it was "being carried out with the supervision of the state attorney and approval of the attorney general". In return, police say Netanyahu operated on Milchan's behalf on USA visa matters, legislated a tax break and connected him with an Indian businessman.
In return, Walla, a news site controlled by Elovitch, allegedly refrained from criticizing Netanyahu and gave him and his wife, Sara Netanyahu, positive coverage.
So far, partners in Netanyahu's governing coalition have stood by him, saying they were awaiting the attorney-general's next moves.
If investigators discover a promise for favorable coverage, Sarah Netanyahu could be charged.
Recent polls show that about half of Israelis believe the police over Netanyahu and think he should step down. In the meantime, Netanyahu is not obligated to resign and has indicated he will fight the charges while remaining in office.