WASHINGTON (CNN) -- A small fire was detected and put out Friday morning in a Senate office building, Capitol Police said.
Authorities don't know who set a fire Friday in a bathroom in the Dirksen Senate Office building.
The fire, set in a women's bathroom in the Dirksen Senate Office Building, is the latest of about seven fires in the Dirksen and Hart buildings in the past two months. Most have been in women's restrooms.
There were no evacuations or injuries, Capitol Police spokeswoman Kimberly Schneider said.
Investigations into the series of small fires are ongoing, but so far, there are no suspects and no one has been arrested, she said.
Four such fires were set October 3 in the Senate's Dirksen and Hart office buildings. Three fires took place in the morning in separate restrooms and were extinguished by police. The D.C. Fire Department was called to the scene of a fourth fire in the Dirksen building later that day.
Two similar fires were started the last week of September in women's restrooms in the Hart building, Capitol Police told CNN. Those fires were set in trash cans, as were the fires in October.
Police have added additional patrols in the office buildings and are asking the public to report any unusual activity or behaviors.
Authorities said in October they did not think the fires were intended to harm anyone.
"This would appear designed to be more of a nuisance than to endanger anyone," said Capitol Police Chief Phillip Morse. E-mail to a friend