Transit police are seeking answers after a passenger claims to have found hateful graffiti scrawled on a Red Line window. 

An MBTA passenger snapped a photo of the phrase "Muslim trash go home!" which she said was written on the interior of the train. The passenger tweeted a photo of the graffiti with the caption, "As seen on @MBTA red line - my heart breaks for our world..."

The T reached out to the rider over Twitter, saying, "Hello. Could you please forward us a car number and current location so we can investigate?"

Transit officials later said on Twitter that they had "isolated the car and were working with the police to investigate and clear the graffiti."

T spokesman Joe Pesaturo told the car was cleaned and returned to service. There was no word on any arrests. 

The incident comes days after a man who proclaimed loyalty to the Islamic State carried out the worst mass shooting in U.S. history. Gunman Omar Mateen killed 49 people and injured more than 50 others at an Orlando nightclub.