Advances in forensic science should mean in future fewer people will get away with murder.

They should also help detectives solve some mysteries which go back 30 or even 40 years.

In some celebrated Sussex murders, police were fairly sure they knew who had committed the crime but were unable to gather enough evidence for a charge or conviction.

One particularly shocking case was that of Keith Lyon, a 12-year-old boy stabbed to death on downland at Woodingdean in 1967.

The knife used for this killing had two types of blood on it. One was Keith's and the other could well be that of the killer.

If that man has a record of any kind, it should now be possible to link him to the crime conclusively through DNA tests.

This man has probably been thinking for many years he will never be convicted. It would be nice for police and the Lyon family if he were proved wrong.