Arlington County police have decided not to charge Patrick Moran in connection with possible voter fraud that came up during his father’s bid for reelection, authorities announced Thursday.

Arlington police and prosecutors initiated an investigation after an undercover video that was released in October showed Moran discussing possible voter fraud with an activist posing as a campaign worker for his father.

Authorities have closed their investigation, saying the person responsible for making the video was uncooperative. They also noted that Moran and the Jim Moran for Congress campaign provided “full cooperation.”

Michael Madigan, attorney for conservative activist James O’Keefe, who posted the video Oct. 8, denied Friday that O’Keefe was uncooperative.

“The police were offered the complete unedited video, which they never followed up with upon receiving,” Madigan said. “James is not in the business of trying to send people to jail. It’s up to the criminal authorities to determine whether there is criminal intent or whether a particular statute was violated.”

Moran, the son of 11-term Rep. James P. Moran Jr. (D-Va.), resigned from his father’s campaign shortly after the video was released.

After the announcement that Patrick Moran would not be charged, O’Keefe e-mailed a statement:

“The video and the subsequent actions of both Patrick Moran and Congressman Moran speak for themselves. What we saw on the video was so obviously damning and inappropriate that Pat Moran immediately resigned, and his father’s office released a statement saying that what he had done was wrong. I don’t need to make any comment beyond that.”

The congressman declined to comment Thursday. His son couldn’t be located.

In the video, Patrick Moran does not explicitly advocate or condone the worker’s suggestion to cast ballots on behalf of 100 voters he says were unlikely to come to the polls on Election Day.

Moran, who appears not to know that he is being recorded, attempts to discourage the worker from carrying out the scheme, saying he should instead join get-out-the-vote efforts. But Moran, who was then a campaign field director, also offers guidance on how to possibly skirt Virginia’s new voter identification laws. He also doesn’t tell the worker not to proceed with his plan.

Patrick Moran ran into additional trouble in December, when he pleaded guilty to assaulting his girlfriend, admitting to a role in an alcohol-fueled incident outside a Northwest Washington night spot.

This article has been updated since it was first published.