Detectives in Lewisham are looking to identify a man in connection with a spate of knifepoint robberies in Brookmill Park SE8.
There have been three incidents recorded on Monday, 30 and Tuesday, 31 August, and Thursday, 2 September.
All of the incidents occurred in the evening between 19:45hrs and 22:00hrs.
In each the suspect has approached couples as they were sat on a bench in the park before pulling a knife and robbing them of their mobile phones.
In the incident on 31 August, a man in his 20s suffered a number of stab injuries. He was rushed to hospital where his injuries were assessed as non life-threatening; he continues to recover.
All of the victims have described the suspect as being a black male, 6ft tall, of skinny build, who was wearing a face mask and hood.
Detectives are urgently investigating and pursuing a number of lines of enquiry.
At this time there have been no arrests.
Detective Sergeant Dan Rouse, of the South East Command Unit, said: "We are extremely concerned by the actions of the suspect, who clearly is a violent offender.
"We are working 24/7 to identify him and we're asking the public to help. I urge anyone who has seen or sees a man in Brookmill Park matching the description of the suspect provided to call 999 immediately. Information as to his identity can be provided to 101.
"Please work with us to help catch this man and remove him from the streets."
Any witnesses or those with information are urged to call 101 ref CAD 7037/31 Aug.
Alternatively contact the independent charity Crimestoppers on 0800 555 111 or