An elderly woman was left disabled after she was mugged in a Birmingham street.
Detectives in Birmingham believe the attacker may be behind up to 15 other street attacks in recent weeks.
He targets elderly and lone women from behind.
One 79-year-old victim suffered a broken kneecap and has only just come out of hospital eight weeks after being shoved to the ground from behind and knocked unconscious. She was attacked in The Greenway, Great Barr, on Monday April 4 at 11.10am.
An hour later the same man is believed to have struck again in nearby Underwood Road when a 68-year-old woman was robbed of her bag.
Det Con Vicki Scott, from Thornhill Road CID, said: "He purposely targets vulnerable members of the community.
"He approaches his victims from behind, mainly elderly women, and some are dragged along the floor by the offender before he steals their handbags and escapes.
"Most of the victims have been women aged 50 to 79 and we need the public's help to catch him."
The robberies have been committed over the past two months in the Rocky Lane and Hamstead area of Great Barr.
He is also known to use a mountain bike. Police believe he lives locally.
He is described as black, in his early 20s, 5ft 8ins tall and stocky, and he usually wears a woollen hat with and a dark coloured tracksuit with white stripes along the sleeves.
Police issued an e-fit of a man they want to question along with CCTV image of the same man using a stolen card outside LLoyds Bank in Grove Lane, Handsworth.