It does not seem that those who commit crimes have the same type of blood, so there is no connection between blood type and human behaviour. All kinds of people – good and bad – share blood types.
What we advise this prisoner to do is to repent to Allaah from whatever crime he has committed, and to restore people’s rights if he has wronged anyone, and to make the most of his life before he dies and of his good health before he falls sick, and to hasten to repent to Allaah. For Allaah will accept the repentance of His slave when he repents, and will forgive him his sins.
There is nothing wrong with giving a blood sample to the state from the point of view of sharee’ah, so long as it will not be put to a bad use and rather it will be used for prisoner records. But the prison administration should be notified that the reason for criminality is not blood type, rather it is corruption of the heart and mind, and growing up with crime and continuing in it.
If they want to deal with it, then they should tackle the root of the problem by looking for the motives to commit crime and the reasons why it develops, then try to put a stop to it and to reform the criminals. There is nothing better than Islam for dealing with that.
And Allaah is the Guide to the straight path.
Sheikh Muhammed Salih Al-Munajjid