At the end of November, 18-year-old John Threlfall was murdered at his home in Lancashire. Police want to trace the strangers asking directions to the house on the day he died. Hertfordshire police want to find the man who raped a young woman, then forced her to drive him to Epping Forest, where she crashed her car to escape. Plus the hunt for raiders who fired indiscriminately in the centre of London after robbing a security van.

The case of Alexander Drummond from near St Andrews in Scotland still puzzles police seven months after his death. Who were the two men seen running towards the farm track where his body was later found? And in Bristol a gang of builders could be responsible for a series of armed robberies between August and December of last year. Twice they broke in overnight through the roof and overpowered building society staff as they arrived for work.

Last month Stefan Kiszko was released from prison after serving a sentence for a murder he did not commit. Lesley Molseed was 11 years old when she went missing on Sunday 5 October 1975. Three days later she was found stabbed to death. West Yorkshire police are now determined to find Lesley's true killer. And witnesses are sought for a case in Guildford where on Saturday 7 December last year a ruthless gang of robbers abducted a jewellery-shop manager as he walked to his car after work.

Three months ago, 14-year-old Tracy Meade went missing from her home in west London. Two weeks later her body was found in the Grand Union Canal. She had been murdered. Hours earlier she had been seen in Shepherd's Bush - police hope someone may have seen who she was with. There's also a report on a chase through London's Covent Garden, which led to the fatal stabbing of Detective Constable Jim Morrison last December, after he discovered a thief rifling through a woman's handbag.

Dinah McNicol , 18 years old, was last seen at a rock festival in Hampshire on Sunday 4 August. Police fear she has been abducted and may be dead. And police are puzzled by the mysterious death of financial director John Shippey , whose body was found five months ago in his car near Redhill, Surrey. Perhaps somebody saw something on the night of Wednesday 18 December.

Jackie Palmer-Radford , a 40-year-old divorcee, was murdered two months ago. Several people were spotted near her house on the day she died, but who were they, and was the killer among them? Lancashire police need help to identify three men who robbed a jeweller's shop in Nelson. The manager was attacked as he tried to fend off the raiders. A Southern Electricity van was hi-jacked, the driver abducted and driven around in the boot of a car for three hours.

In Cheshire a bank manager's wife was held to ransom in the boot of a car for several hours. Her husband delivered the money after instructions were placed on his car windscreen. Did you see someone put them there? Did you see the man who followed him in a blue Ford Orion? And three months ago Katie Rackcliff was stabbed to death in the early morning. Did anyone see the loner watching her in the nightclub, hours before she died?

On Saturday 1 August, guests at a wedding reception found the body of 15-year-old schoolgirl Helen Gorrie. She had been strangled. The previous evening a witness thought she saw Helen talking to two men. Will you recognise the videofit of one of them? Did you see anything unusual that night along the old A3 in Horndean? In Milton Keynes , a number of attacks, including two rapes, have taken place this year. Nearly all the incidents took place around the Fishermead Estate and police believe one man is responsible. Have you have seen anything suspicious?

Two months ago a botanist discovered the body of a prostitute, stabbed to death, in dense undergrowth in north Yorkshire. A witness remembers seeing someone like her talking to a man shortly before her death. Who is he? In Lambourn a security guard was shot as he made a delivery. A reconstruction of the event - with impressions of the gang's faces - and the guard's own story may jog memories.

Among the appeals featured tonight is a crime that took place in Frinton-on-Sea on Thursday 27 August. A Post Office van was making a routine delivery when the guards were attacked by armed robbers. Police believe four men were involved and are anxious to trace a white Sierra Sapphire and a black J-reg Alfa Romeo. Both cars followed the van until it was abandoned in a nightclub car park about seven miles away. Crimewatch UK will be showing two artists' impressions of the hijackers and reconstructing events in the hope that a viewer might remember where the cars went next.