Police are searching for a thug who they believe has carried out a series of robberies in the same neighbourhood, knocking some of his victims unconscious.
The man targeted two men in the West End area of Leicester earlier this month.
Officers released details of the attacks today and said they were not ruling out the possibility they were linked to two similar incidents in the same area last month.
Victims have not been able to provide a description of the attacker because of the sudden and rapid nature of the assaults.
People have been urged to follow simple personal safety tips when they are out and about in the area, especially late at night or in the early hours .
In the most recent incident, a 20-year-old man was punched while he was walking through Bede Park.
His attacker stole his phone and wallet.
A short time before or after, a 24-year-old man was assaulted in a similar fashion near the junction of Narborough Road and Hinckley Road.
Nothing was taken from the victim.
Both men received medical treatment for their injuries following the attacks, which happened at about 4am on Saturday, June 4.
Detective Constable James Collins said: "I am appealing to anybody who was out in the area in the early hours of June 4 who may have seen what happened and could assist our investigation.
"Any information, no matter how insignificant it may seem to you, could help with our inquiries."
The attacks have happened in and around Narborough Road.
A Leicestershire Police spokeswoman said officers were "keeping an open mind" on whether the attacks were carried out by a man who targeted the same area last month.
In those cases, a thug knocked a man and a woman unconscious before stealing their phones and other valuables.
Those attacks happened in the same area of Narborough Road in the early hours of Sunday, May 22.
The woman was attacked on a path between Narborough Road and King Richard's Road and the man a short distance away at the junction of Hinckley Road and Braunstone Gate.
Police advise people to keep valuables such as phones and laptop computers out of sight, to wear bags over the shoulder and to cover up jewellery with a scarf or clothing.
They are also encouraging people to be aware of their surroundings and to change direction if they begin to feel unsafe and to use well-lit, busy streets if possible, and also a route they are familiar with.
If you have any information, contact Det Con Collins on 101 or Crimestoppers, which is anonymous, on 0800 555 111.
