U.S. Capitol Police on Friday were investigating the latest in a series of suspicious fires occurring in Senate office buildings.

Police spokeswoman Sgt. Kimberly Schneider said a small fire was discovered about 8 a.m. in a second floor woman's restroom of the Dirksen Senate Office Building. She said it was quickly extinguished and there were no evacuations or injuries.

Schneider said it was at least the seventh confirmed fire in the office buildings since late September. The fires are all suspicious in nature and Capitol Police are exploring the possibility that they are linked, she said.

Capitol Police sent out a mass e-mail in early October noting "a series of small fires that have occurred in the Senate Office Buildings in recent days," and asking for tips. The e-mail said that more building patrols have been added to investigate.