Transit Police are investigating whether a 20-year-old woman of Vietnamese descent had her civil rights violated this Saturday when a man called her a racial epithet and blocked her from entering a Red Line train, authorities said.

According to Transit Police Lieutenant Richard Sullivan, the woman was at the Downtown Crossing station around 6 p.m. and was trying to board a southbound Red Line train when a man “stepped in front of her in a threatening manner and issued a racial slur directed at her.’’

Once the woman boarded the train, Sullivan said in a statement, the man allegedly continued to harass the woman. When she did find her way onto a subway car, the man allegedly followed her and then sat down across from her, Sullivan said.