NEW ORLEANS (AP) — Conservative activist-videographer James O'Keefe said video he shot of conversations with staffers of U.S. Sen. Mary Landrieu was deleted when his cell phone was returned after he and three others pleaded guilty to charges in a caper he orchestrated at the Democrat's New Orleans office.

A spokeswoman for the U.S. attorney's office said Saturday that U.S. Magistrate Daniel Knowles III ordered the footage removed. O'Keefe made the claim Friday in a posting on his Twitter social networking site.

O'Keefe, 25, and the others pleaded guilty on Wednesday to misdemeanor charges of entering federal property under false pretenses. They were sentenced by Knowles.

They were sentenced to probation, community service and fines. O'Keefe received the heaviest sentence, three years probation, 100 hours of community service and a $1,500 fine.

The FBI has said O'Keefe used his cell phone to try to capture video of two others who posed as telephone repairmen and asked to see the phones at Landrieu's office. O'Keefe has said the group was trying to investigate complaints that constituents calling Landrieu's office couldn't get through to criticize the Democrat's support of a health care reform bill.

O'Keefe, who apologized after his sentencing for raising security concerns at the federal building that houses Landrieu's office, said he would continue his undercover work.

He is best known for posing as a pimp in a video that embarrassed the community organizing group ACORN.

O'Keefe, Stan Dai, Joseph Basel and Robert Flanagan were arrested Jan. 25 on felony charges, but federal prosecutors later reduced the charges.