Three thugs threatened a man with a knife near Leicester railway station and ordered him to hand over his money.
Two men and a woman confronted the 20-year-old victim but he managed to run away and alerted police officers who were nearby.
The attack took place in London Road, near Conduit Street at 5.30pm on Monday, February 25. Police released details today.
Pc Mark Lacey said: "Thankfully the victim was not hurt but the results of this could have been much worse and I would appeal for anyone with information about the incident to come forward.
"The incident happened at a busy time of the day at busy area of the city, so I'm hopeful that anyone who did witness the incident will be able to help us."
One of the men is described as black and aged between 30 and 40 years old. He is described as having yellow teeth and long black hair. He was wearing a brown jacket, jeans, black shoes and a hat.
A 31-year-old man and a 38-year-old woman have been arrested in connection with the incident. They have been released on police bail while officers continue their inquiries.
Contact Pc Lacey on 101 or Crimestoppers, which is anonymous, on 0800 555 111.