Someone spit on and assaulted a person with a disability on the T at Harvard Square in Cambridge on Wednesday morning, transit police said Friday.
Police are asking the public's help to identify a person of interest they would like to question in the attack, which took place at about 11:15 a.m.
They released photos of the person to the public.
In-depth news coverage of the Greater Boston Area.
Anyone who knows the person in the photographs is urged to call MBTA police at 617-222-1050 or text a tip anonymously to 873873.