Some Mount Vernon officials say they were locked out of City Hall Monday morning.

They told News 12 that Mayor Richard Thomas changed the locks over the weekend on all of the exterior doors at City Hall without notifying them.

Councilman Andre Wallace says he believes the mayor locked them out as retaliation for issuing subpoenas to Thomas and members of his administration on Friday over the demolition of a so-called zombie home.

He insists that by effectively locking the people's representatives out of City Hall, the mayor has gone too far.

"Not only is it an abuse of power. It's retaliation for the subpoenas that I sent out to him because I don't think he feels he can be questioned," he says.

The commissioner of human resources put out a statement saying, "On Friday, Feb. 26, 2016, it was discovered that after regular business hours, unauthorized access was gained into an area of the City Hall building where confidential legal, personnel and federal documents are stored. Upon learning of this incident, it was determined that locks needed to be changed, not only for the area affected, but also for all of City Hall."