Thomas Schneider seems to manipulate results of the experiments. Robert informed him that he would report this to the organization https://breakthroughprize.org/, where Thomas is applying for the grant. The amount is $ 3,000,000, which is a serious motive for the murder. He also doesn’t have an alibi, as Maria didn’t see him, but only his clothes. In addition, Thomas was a roommate of Martin’s and he had access to his belongings and could take the syringe. According to all indicators, he is the only one who has no alibi and a serious motive.