I wonder what happens to large evidence IE the car in unsolved cases?
do they keep it? as today it could serve up a wealth of DNA
I doubt the police would have kept it Arfur, chances are they would have returned it to it's owner Lucan's friend Michael Stoop after they had finished with it. Although only eight years old at the time of the murder, the Ford Corsair was generally described as an 'old banger' and a second car to Stoop's Mercedes. The interior had been heavily bloodstained and it would be hard to imagine Stoop wanting to hold on to it after all that had happened, it was probably scrapped long ago.
But you are right, had they had DNA in 1974 it would have yielded a wealth of information.