Sen. Leanna Washington, D-Philadelphia, said in a statement through a spokeswoman that the agents arrived at her Philadelphia and Montgomery County offices on Friday.
Washington's office would not immediately say what they agents wanted or what they took. But two people familiar with a search warrant provided by the attorney general's office said the agents were seeking boxes of information or paraphernalia related to political activity and copies of information on the offices' computers.
The people spoke on condition of anonymity because they were not authorized to speak publicly about the matter.
Joe Peters, a spokesman for Attorney General Kathleen Kane, a Democrat, said Sunday that he could not confirm or deny whether the office's agents searched Washington's offices or the existence of any investigation into Washington.
The Philadelphia Inquirer first reported on the search warrant.
The Senate Democratic caucus issued a statement through a spokeswoman saying they were aware that the attorney general's office was seeking information concerning Washington's office and that they would fully comply and cooperate with prosecutors.
Washington, 68, was elected to the Senate in 2005 and is the Democratic chairwoman of the Senate Aging and Youth Committee. Before that, she served 12 years in the state House of Representatives.
Typically, a search warrant must be approved by a judge before it can be executed by investigators and is public unless sealed by a judge. Using taxpayer-paid resources to aid campaign or political activity is illegal.