Police have released footage of a man being kicked off a tram platform on to the tracks.
The 23-year-old victim arrived at Didsbury Village Metrolink station in Manchester at the same time as a man and two women at about 10.50pm on Friday October 13.
After the male in the group put on a balaclava, the victim was tricked into assisting one of the women who ran on to the tracks.
As he turned to help the woman back on to the platform, the disguised male kicked him from behind and off the platform.
The victim was then threatened with a metal bar and a wine bottle after he clambered back on to the platform before he fled to safety.
Police are linking the incident with an attack minutes later on a 66-year-old man who was beaten over the head with a metal bar in Beaver Road, Didsbury.
The pensioner is recovering at home after he suffered a heart attack and was treated for head injuries.
Detective Constable Phil Whiting, of Greater Manchester Police, said: "Around the time of both incidents there weren't a lot of people around. However, I'm sure that by looking at what the people in the footage were wearing, someone will remember them being together.
"I appreciate the man has his face covered but it may be you recognise the way he walks or the clothes that he is wearing.
"We need to speak to these people as a matter of urgency so I want people to really study the footage; their faces, the way they are holding themselves and how they are acting. You may have seen them holding bottles of wine or a metal bar.
"If you know who they are or saw them around the time of either incident, please call us."
Anyone with information should contact police on 0161 856 6153 quoting reference number 2533 of 13/10/17, or independent charity Crimestoppers, anonymously, on 0800 555 111.