Israeli police say they have found no evidence Israel's opposition leader broke campaign finance laws in the Labor Party's primaries in 2013.

Police had been investigating whether Isaac Herzog secretly accepted a donation of about $10,500 to fund a negative ad campaign against his opponent. They say Herzog's campaign didn't report the donation to authorities at the time. Herzog denied wrongdoing.

On Thursday, police said a businessman whose work was affected by pending legislation donated the funds through a senior campaign staffer, but that there is no evidence that Herzog knew about the donation.

Police say they did find evidence of wrongdoing by the campaign staffer and the donor.

After securing the leadership of the party, Herzog ran against Prime Minister Benjamin Netanyahu in last year's national elections, but lost.