Officers continue to probe the killing of the 22-year-old mother of three, whose body was concealed by a small hedge near Lambert's Restaurant on the A464 Shifnal to Wolverhampton road in 1991.
West Mercia Police spokesman Chris Ammonds said today that fresh work was being undertaken to identify Miss Downes's killer.
The new investigation is part of a procedure in which cold cases are revisited. Evidence from the time is being re-examined using the most modern forensic techniques, some of which were not available at the time of the murder.
Mr Ammonds said: "There are investigations still going on. There is forensic work being re-examined and we are really keen to speak to anyone with information about Janine's death."
The body of Miss Downes, who had worked as a prostitute, was found just before 9.30am on February 2, 1991. Following her death, a post-mortem examination showed she was strangled and had extensive head wounds. She had been sexually assaulted.
Clothes from the bottom half of Miss Downes's body and her trainers were missing.
Following the killing, a West Mercia Police pathologist estimated that her body had been left there between midnight and 4am.
Her last known movements were in Wolverhampton's red light district and detectives believed that Janine had been killed by a client.
Detectives revealed in 2011 that they were following up potential new leads after a fresh appeal led to a number of phone calls.
Two years ago, the detective leading the hunt for the killer said he was convinced someone knew who killed her as he revisited the lay-by.
Detective Chief Inspector Neil Jamieson added someone was withholding a 'nugget' of information that could lead them to the killer.
Miss Downes was said to be from a broken home and was in and out of care homes and turned to prostitution out of desperation.