Detectives investigating the murder of a gay bar manager on Clapham Common believe his killers may have verbally abused a woman moments earlier.
Mr Dobrowski suffered head, neck and facial injuries
Jody Dobrowski, 24, was found beaten in south London at midnight on Saturday.
Fifteen minutes earlier, two men matching descriptions of Mr Dobrowski's killers, had made sexual comments to a woman in nearby Battersea Rise.
Police want to speak to anyone involved in a similar encounter. Three teenagers have been arrested and bailed.
Mr Dobrowski died from head, neck and facial injuries in what police believe was a homophobic attack.
Det Chief Insp Nick Scola said: "Although this was a brief and distressing encounter for the woman, she has been able to provide good descriptions which closely match the description of Jody's murderers."
They are both white, aged between 20 and 30, and one is notably taller than the other.
He added: "I would appeal to anyone who had a similar encounter with these men or who may have seen them in the area earlier in the evening.
"If it was you involved in this incident please come forward so you can be eliminated from the inquiry."
The two 17-year-olds and a 13-year-old, arrested in Battersea, south-west London, have been released on bail.
Earlier detectives appealed for about 10 or 12 people they believed were on the common at the time, to come forward.
Police also want to trace Mr Dobrowski's movements between 2215 BST, when he left a friend's house near the common, and just after midnight when the police found him.
Detectives are examining whether there is a link between Mr Dobrowski's murder and a series of homophobic attacks in the area.