A journalist says he went undercover to expose problems in the Yonkers Federation of Teachers union.

Journalist James O'Keefe released a 17-minute video involving leaders of the union, that he says proves the Federation of Teachers cares more about its members than it does about kids.

In the video, O'Keefe posed as a Yonkers teacher who admitted to assaulting a student.

He says an apparent exchange between YFT Vice President Paul Diamond and himself shows the union puts kids at risk.

"No arbitrator is going to take your livelihood away from you for one incident," said Diamond on the video.

O'Keefe claims the video even shows how Union President Pat Puleo told him how to explain a fake, unexcused two-week absence to Mexico that occurred after the assault.

Puleo says the video is nothing more than another example of O'Keefe's lying and deceptive tactics to try and take down organizations that disagree with his politics.

The Yonkers school district has no jurisdiction over the union, but in a statement, Superintendent of Schools Edwin Quezada said after the video came to his attention, he immediately contacted the legal department for their review.

Over the past few years, O'Keefe has used controversial tactics in undercover stings against organizations like ACORN, and most famously Planned Parenthood. The videos of Planned Parenthood employees allegedly selling fetal tissue led to Congressional hearings and calls to defund the organization.