Melbourne tram stabber still on the loose

Investigators are still searching for a man who stabbed two Melbourne tram passengers.

The pair in their 20s needed hospital treatment after last Friday's stabbing on a Footscray tram and detectives are seeking a man of African appearance who at the time wore a dark overcoat, beanie and scarf.

Three days after the incident officers arrested a 56-year-old man in connection with the stabbing but he has since been released without charge.