Energy and Water Minister Silvan Shalom (Likud) was identified on Monday afternoon as the previously unnamed senior minister being investigated by police for a sexual assault that was alleged to have taken place 15 years ago.

The National Fraud Unit, which handles high-level corruption investigations, opened a probe into claims of a woman who said she was sexually assaulted or abused by Shalom 15 years ago, when she served under the then-science minister in the first Netanyahu government, police announced earlier Monday.

Police said they were treating the allegations as a serious matter, since a single complaint often leads other alleged victims to come forward.

Sources close to Shalom have denied the allegations vehemently, saying he did not even know the woman in question.

“This is political assassination. I have no idea what they’re talking about. I’ve never heard the woman’s name in my life,” Shalom’s confidants have quoted him saying.

Some sources suggested the allegations were a smear campaign related to the race to replace President Shimon Peres when he leaves the presidency in July. Shalom is thought to be one of the front-runners in the race.

Evaluations of the woman’s polygraph were inconsistent, determining both that she was telling the truth but also that she had a “tendency to lie,” according to police.

Attorney General Yehuda Weinstein is expected to hold a meeting with police and Justice Ministry officials when their preliminary investigation is complete in order to decide whether to file charges. Among the legal questions raised by the case is the possibility that, based on the nature and severity of the alleged crime, the statute of limitations for prosecution has passed.

Army Radio aired a recording of the complainant, who has still not been identified in the media, recounting the alleged incident.

Reports of Weinstein’s investigation and the allegations first surfaced Sunday.