Detectives investigating the 1992 murder of a Norwich teenager have been given fresh hope after receiving new calls and emails about the case.
Natalie Pearman was found dead in a lay-by at Ringland Road, Norwich, in the early hours on 20 November.
A post-mortem examination found the 16-year-old, who had been working as a prostitute, was suffocated.
Norfolk Police said they had received 20 calls and emails since renewing their appeal for information last week.
A YouTube video made by police was released to try to jog people's memories.
Det Ch Insp Andy Guy said: "We have had an encouraging response to the anniversary appeal regarding Natalie's death and are consequently pursuing some lines of inquiry.
"We welcome any new information or leads that may help explain the circumstances surrounding her death."
'Plays on conscience'
Natalie's body was found by a lorry driver at about 03:50 GMT. She was last seen alive in Rouen Road, Norwich, at 01:15 GMT the same day.
Police said there were signs of sexual activity shortly before her death.
At the time of the initial investigation, DNA samples were taken but no match has yet been found.
Over the years, more than 4,000 people have been interviewed and hundreds of men have provided DNA samples for testing.
Detectives have probed possible links to Steve Wright, who murdered five women in Ipswich, and serial killer Peter Tobin, but without success.
"Just one piece of information could hold the key to solving this murder case. No matter how insignificant they think it might be, I'd urge them to call us," said Mr Guy.
"There are people who know or strongly suspect who was responsible and I'm sure that plays heavily on their conscience."
He added anyone with information should contact the police's cold case team or ring Crimestoppers anonymously.