Four conservative activists accused of trying to tamper with the phones in Sen. Mary Landrieu's office pleaded guilty Wednesday to misdemeanor charges of entering federal property under false pretenses.
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. The fourth allegedly waited outside in a car with a listening device.
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.
Magistrate Daniel Knowles III sentenced the three other suspects to two years probation, 75 hours of community service and $1,500 fines.
Protesters marched in front of Landrieu's office in Baton Rouge last December to criticize her support for Senate health care legislation and complain they couldn't get through on her office phones. Landrieu said at the time that her office was receiving a high volume of calls and apologized.
After sentencing Wednesday, O'Keefe and the others were taken to a probation office for processing. O'Keefe said he might release a statement later in the day.