WATCH: Detectives tell Clyde News they won't give up looking for Caroline Glachan's killer

'We'll never give up looking for her murderer' - the message from detectives hunting the person who killed Bonhill school girl Caroline Glachan 21 years ago today.

Earlier this week we heard from the 14 year-old's mum, Margaret McKeich, who told us she still has confidence in the police.

They have re-released an image of a hooded man they want to trace and Superintendent Jim Kerr says they are taking their time to make sure any arrests will stand up in court.

He spoke to our reporter Natalie Crawford:

Forensic experts at the Scottish Policing Authority are still examining more than 300 pieces of historic evidence and 200 witness statements.

Detectives are certain that the answer to her murder lies in the local community, and one year on from the re-investigation, they remain hopeful that they will trace whoever is responsible for her murder.

Senior Investigating Officer, Detective Superintendent Jim Kerr said:

“It's now been a year since we announced the reinvestigation into Caroline’s murder. A good amount of progress has been made since then and we've been working very closely with forensic scientists at the Scottish Crime Campus. The Scottish Crime Campus houses one of the most advanced DNA testing laboratories in Europe. A large number of the 300 pieces of evidence continue to be carefully examined for traces of DNA, and the painstaking work that the scientists have been carrying out continues.

"Following our reappeal, we've had calls from as far away as Australia with information, from people who lived in the area of Bonhill and Renton at the time of the murder. Our work over the last year has continued to review the initial investigation and visiting those who were witnesses at the time to take reference samples of DNA.

"We remain in contact with Caroline's mother Margaret and the support we receive from her and her family during our investigation remains crucial.

"We continue to reappeal to anyone with information that will assist the ongoing investigation to do the right thing and come forward. Caroline’s friend Joanne Menzies was one of the last people to see Caroline. Caroline left Joanne at the Bonhill shops at 2354 hours. Caroline was last seen around 0015 hours when she walked down Dillichip Loan towards Dillichip Bridge which was known locally as the Black Bridge (no longer exists) and then onto the tow path.

“I would appeal again for assistance in tracing a man wearing a dark green hooded top who was seen by a taxi driver walking near Caroline as she made her way along Dillichip Loan around 0015 hours on Sunday 25 August 1996. The man has sharp features and may well be the last person to see Caroline alive, however despite previous appeals to identify him, he has never been traced. Witnesses have also spoken of hearing people arguing or shouting in that area a short time later.

"I know there has been a reluctance from people in the Bonhill and Renton areas to come forward in the past with vital information on this murder. However can I remind people that we are investgiating the murder of a 14 year old girl - a young girl who is sorely missed by her family and friends.

"Someone out there who stayed in that community at that time holds the vital information we need - there is no doubt in that."

Anyone with information should contact the Operation Fairing Team through 101. Email officers through operationfairing@scotland.pnn.police.uk. Alternatively CRIMESTOPPERS can be contacted on 0800 555 111, where anonymity can be maintained