This happened to some friends of mine this week. 7am and there is a series of large knocks on the front door. They answer and standing thee are two policemen, another two are at the bottom of the drive and there are twopolice cars parked in the street. The cops ask if their 19 year old son is at home. He is. They see him and arrest him for criminal damage. He is handcuffed and escorted to the car and taken away! It turns out that 3 months ago someone threw a bottle through the window of a parked car. The bottle was tested for DNA and it matched the DNA of my friends' son! 2 years earleier he had been the victim of a street robbery and his DNA had been taken to eliminate him from DNA evidence found at the crime scene. As it happened the son was able to prove that he had been on holiday in Spain when the bottle had gone into the car! And so was released. This just seems so bizarre and OTT. Firstly whose car was it that such minor damage neded the input and expense of a forensic examination involving DNA. Why is the lad's DNA kept on file even though he was not a criminal? Why did it need 4 policemen and handcuffs to take him away when surely a few questions asked at the house would have sufficed for the time being and given them things they could check before making an arrest. Presumably the bottle had been picked up from a recycling bin or from a pub and it was pure chance that he had been drinking from it.