A woman dressed in a bunny suit and three other people are wanted by police after an assault on a train from Birmingham's Moor Street station.
British Transport Police has released CCTV pictures of the woman and three men after 12 friends from Worcester were attacked on the 06:10 train service on 2 November.
The attackers got off at Old Hill station in Warley according to police.
PC Brendan Gilbride, from British Transport Police, said:
"Members of the group were subjected to an unprovoked assault by another group who were on the same train".
"The train driver managed to split the two groups up and the victims left the train."