A boy aged as young as 12 may have carried out several sex attacks around a university campus, police said.
Greater Manchester Police is linking three assaults that have taken place in the past month near the University of Manchester.
A computerised image showing how young the offender was made the incidents “even more shocking”, police said.
The first two attacks took place within 15 minutes of each other on 21 September.
A 27-year-old was approached from behind and grabbed in Lloyd Street North at 18:15 BST before she screamed and the offender ran off.
The next incident followed in Oxford Road when a 21-year-old woman was approached by a boy who made lewd comments as she left John Rylands library.
She carried on walking on Moss Lane East and was sexually assaulted by her assailant who was described as a young boy aged 12 who wore green jeans and glasses.
The third attack took place at the Manchester Science Park in Lloyd Street South at about 14:15 BST on 5 October.
A 32-year-old woman was approached by two young boys and sexually assaulted by one of them described as of Asian heritage, 12 to 13 years old, of slim build, with a small frame who wore baggy trousers and carried a rucksack.
She pushed the boy away but he approached her again and sexually assaulted her for a second time before running off towards Pencroft Way with a second child.
Det Con Pam Collins from Longsight Police Station said: “After speaking to the women, we have managed to complete an evofit of the offender. As you can see from the image he looks fairly young which makes these assaults even more shocking.
“After each woman has told the offender to go away he has followed this up with violent threats so we are keen to find this individual as soon as possible.
“I would ask anyone who either recognises the image, witnessed any of the assaults or may have fallen victim to this person to call us.”
Anyone with information should contact Greater Manchester Police.