Updated: 5:03 p.m.

The Houston Police Department said an air gun is likely to blame for damage caused to Rep. Gene Green’s district office Tuesday morning.

Local Fox affiliate KVIR first reported that shots were fired near the Texas Democrat’s office, but police spokesman John Cannon said the incident looks to be a case of criminal mischief.

“Our officer took a look at the damage done to the window, and it appears to be damage from a BB or a pellet gun,” Cannon said.

There were no witnesses or suspects, he added.

Nevertheless, the incident rattled staff, who notified Capitol Police and local authorities around 11 a.m., believing the office’s windows had been damaged by gunshots. The 10-term Congressman was out of the office at the time, a spokeswoman confirmed.

Some employees were in the office, but nobody was injured, the staffer confirmed.

A building next door was also damaged, the spokeswoman said.

Lawmakers have put more of an emphasis on their own security after Rep. Gabrielle Giffords (D-Ariz.) was shot earlier this year.

Green has recently faced angry constituents.

At a contentious town hall meeting earlier this month, Green was called a coward and faced criticism from both Democrats and Republicans for backing the debt ceiling compromise legislation. Afterwards, Green told Roll Call that while he understood the crowd’s anger, he did not think tensions were as high as they were two years ago amid the health care debate.

“This was mild compared to what I went through in ‘09,” Green said at the town hall meeting in Houston on August 17. “People are frustrated. What Congress does very publicly and the disagreements we have don’t give people around the country what they want, [which] is stability.”

As he defended his decision to back the debt ceiling compromise despite the cuts it may make in social programs he supports, Green added, “Democracy’s not designed to be efficient.”