PHILADELPHIA -- Sen. Frank Lautenberg is demanding a response from the National Rifle Association regarding charges it placed a paid spy in gun-control organizations for more than a decade.

The powerful firearms lobby hasn't said a word since reports arose last week that 62-year-old Mary McFate, who portrayed herself as a gun-control activist, might really have been snooping on several nonviolence groups on behalf of the NRA.

The New Jersey Democrat wants the NRA to confirm or deny the charge, reveal what, if anything, she was paid, disclose the names of any other informants, and put a stop to the practice.

Gun-control groups are exploring whether any laws were broken.

McFate has already been expelled from one group. A second group will likely do the same Friday.