Sam Rosenberg is clearing the air and defending his active shooter security training course after the North Allegheny School District decided to abruptly cancel his ASSERT program.

His McCandless area security firm, INPAX Academy of Personal Protection, was set to teach the free hands-on course to parents following the mass shooting at a Florida high school.

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"We were surprised! We knew that there was a sort of concerned parent complaint," he said.

The district announced just before the Wednesday night class that it was canceled because of "unforeseen circumstances."

The North Allegheny Schools Superintendent said, in part, that “a district parent shared concerns regarding inappropriate content on social media channels affiliated with INPAX.”

The district alleged those posts violated district policy and weren't in line with their mission or vision.

Rosenberg said the old posts were dug up from his personal Facebook page and weren’t meant to cause harm, but the damage apparently had already been done.

"I was very surprised by that, but at the same time, listen... that was their decision. I understand it. I hope that we have an opportunity to continue our relationship," he said.

"We welcome everybody. This is not about anyone's opinions. About anything political or anything else ... this is about safety."