British Transport Police are appealing for information about an incident at Kings Norton rail station on Thursday night which left a man with a neck wound.
Detectives believe a number of passengers were at the station when the incident took place at around 8pm on June 3 and are keen for them to come forward to assist the investigation.
Officers are still trying to piece together the full circumstances leading up to the incident which resulted in the man needing hospital treatment.
Detective Sergeant Shanie Erwin, who is leading the investigation, said: “At this stage, it remains unclear exactly how the man received the injuries which, although serious, are not life-threatening.
“Officers are continuing to view CCTV from the station and other locations and are speaking to witnesses to build up a full picture about what happened.
“We believe a number of people who were at Kings Norton railway station at around 8pm on Thursday may have information which could be vital to us.
“I would urge anyone with information to come forward and speak to us straight away in strict confidence.”
Anyone who witnessed the incident, or who has information which could assist the investigation, is asked to contact British Transport Police on 0800 40 50 40, quoting incident number 605 of 03/06/2010, or Crimestoppers anonymously on 0800 555 111.