PHILADELPHIA — A former Democratic state lawmaker fighting corruption charges told jurors he destroyed computer files because he feared partisan investigations by the Bush-era Justice Department.

Ex-Sen. Vincent Fumo endured a fifth day on the witness stand in his federal fraud and obstruction case, and will return today for a sixth, and perhaps final, day.

A federal prosecutor grilled Fumo about e-mails that suggest the senator ordered his staff to destroy old e-mails even though he knew the FBI was investigating a $17 million gift from a utility company to a Fumo-linked charity.

Fumo said he had implemented the e-mail security policy — which also wiped clean a state server where backup copies were stored — because of concerns about Justice Department surveillance.

"They were going after Democrats all over the country," Fumo testified. "I was a target because I was the most prominent Democrat in Pennsylvania."

He added, without elaborating: "We're talking about Karl Rove here, we're talking about Alberto Gonzales, who specifically asked about me at the White House."

Fumo, a longtime Philadelphia power broker, is accused of misusing millions that belonged to the state, a maritime museum and a nonprofit community group to fund a lavish lifestyle. Fumo founded the nonprofit and the millions he raised for it included the big donation from electric utility Peco Energy, a gift that coincided with deregulation talks.

Fumo's testimony Tuesday was the first time he has blamed the federal charges on a partisan Justice Department under George W. Bush.

Prosecutors are nearly finished their cross-examination, but today could bring another showdown in the hard-fought case. Fumo's longtime friend, lawyer and a man he has described as a "father figure" — attorney Richard Sprague — is expected to testify for the government on rebuttal.