Sophia Grace Posted over 1 year ago Why Can't Improperly Obtained Evidence Be Used In A Criminal Trial? When evidence obtained illegally cannot be used, it is simply because, no one can be sure it is legitimate. You cannot just show up with a bloody knife, claiming it was taken from the accused's home - you have to be able to prove it. Another thing is the rights of an individual. A lot of people are questioned by the police during an investigation... most of them will be innocent of the crime and should not have their home/work searched and money, computers or other items seized. The law has to be equal for all. We are all innocents until proven guilty, and even criminals have rights - they might be guilty of a crime, but should not automatically have the right to be innocent until proven guilty taken away in other cases. The entire concept of a court is, that one is innocent until a verdict decides otherwise. All doubts should benefit the accused.