Jeremy Bamber was in his early twenties when his family was shot and killed, with the initial investigation suggesting that his sister had perpetrated the shooting - having been found holding a gun beneath her chin in one hand, and a bible in the other. This was further solidified by the long history of mental health problems that Bamber’s sister had suffered from.
It was Bamber’s cavalier behaviour after the crime that arose suspicion, and soon circumstantial evidence began to mount against him - such as a throwaway remark he made to his girlfriend about hiring a hitman to kill his family. Eventually the police was presented with a silencer used in the crime hidden in the barn, signifying that Bamber’s sister had not completed suicide but had also been murdered along with the rest of her family.
Bamber was arrested and charged with his family’s murders, including the deaths of his two 6 year old nephews, and was found guilty. Bamber has fought this conviction but it has continually been upheld by courts.