The police investigators have begun questioning the Israeli Prime Minister Benjamin Netanyahu over suspicions that he received gifts from businessmen, Reuters reported.
The decision came after Attorney General Avichai Mandelblit conducted a prelimnary enquiry and was satisfied that there was enough evidence to question the prime minister.
Israeli newspaper Haaretz reported that the police had deposed several witnesses in the case including Jewish American businessman Ron Lauder who is considered close to Netanyahu.
Israeli media said the questioning which started on Monday evening was expected to last several hours, reported Reuters.
Netanyahu asked his oppnents to "wait with the celebrations, don't rush. I've said it before and I'll say it once again: there will be nothing because there is nothing".
Channel 2, a commercial network, said the investigation was one of two cases now open against the prime minister, although it said details of the second remained unclear, a report in the news agency Reuters stated.
Netanyahu is not the first prime minister to be questioned in a criminal case.
Ehud Olmert is currently serving a prison sentence on charges of breach of trust and bribery. Aerial Sharon was also questioned over allegations of bribery and corruption.
Netanyahu will become Israel's longest serving leader if he stays in office until the end of next year.