Israeli Prime Minister Benjamin Netanyahu was questioned on suspicion of corruption for more than three hours in his home Monday night, according to CNN.
Israeli police spokesman Micky Rosenfeld told CNN Netanyahu is suspected of allegedly accepting gifts from wealthy supporters.
Attorney General Avichai Mandelblit made the decision to open a criminal investigation after a preliminary inquiry, according to Reuters.
"The nature of the investigation precludes us at this stage from giving details of the ongoing investigation but we will consider releasing more information from time to time according to developments," Mandelblit said in a statement to Reuters.
Israel’s Channel 2 TV reported that the investigation is one of two cases open against the prime minister.
An Israeli newspaper reported that Netanyahu's friend, Ronald Lauder, who happens to be a billionaire, is linked to the investigation.
The Israeli leader has repeatedly denied any wrongdoing, saying the claims against him are politically motivated.
On New Year's Day, Netanyahu posted to his Facebook page saying, "Unfortunately you'll have to be disappointed this time as well, like you were disappointed in previous affairs. As usual, there will not be anything because there is nothing. Try replacing the Prime Minister at the ballot box -- as is customary in a democracy."
Netanyahu isn't the first prime minister to come under investigation for alleged corruption.
Reuters reports that former prime minister Ariel Sharon was questioned in 2003 and 2004. In addition, former prime minister Ehud Olmert was convicted of corruption charges and is now serving a prison sentence, according to CNN.