Appearing at Cambridge Crown Court on Monday, Ashley White told the court he had witnessed Jordan Shepherd kill Mr Mechelewski at the country park on January 31 last year but had been scared to admit it.White, 20 of West End, Brampton, and Shepherd, 23, of Mayfly Close, Chatteris, are both charged with the murder of Mr Mechelewski. Both have denied the crime. The court heard how White had originally lied about his whereabouts on the night of the murder but, a month before his trial was due to begin, changed his statement. He said: I was scared to admit that I saw him [Shepherd] killing Sam. It wasnt until I got a full understanding of what was going on that I decided to tell the truth. The court heard how, in his changed statement, White claimed Shepherd had threatened to kill him and his family if he told police what he had seen. The statement, which was read out in court, said: It all happened so quickly. At some point Shepherd ran over to Sam and, as Sam turned around, stabbed him in the side of the neck. He said to me that if I went to the police he would do the same to me and my family. However, Shepherds defence counsel, Richard Barraclough QC, suggested that White had only changed his story because of a police recording in which he admitted to others that he had been present at the murder, something he had originally denied. Mr Barraclough said: I suggest that you only came clean because there was a secret recording of you talking to people in prison admitting that you were there. White denied this, however, and said that he wanted to tell the truth, as he knew it would come out in the end. Both White and Shepherd claim the other was responsible for the murder. It is prosecutor Richard Christies case, however, that both defendants planned the murder together. He told the court that it had been concluded by forensic teams that Mr Mechelewski, 20, from Huntingdon, suffered numerous injuries to his head. The manner of the injuries, Mr Christie told the court, suggested it would have needed two people to participate. Mr Christie said: I suggest that you were both in it together. He [Mechelewski] was hit around the head with a baseball bat. What we know from these injuries is that he had sustained no fewer than two blows on his head. Then two stab wounds - one to the left of his neck, a slicing wound, and one penetrating right from into his body and into his throat. Thats because you were doing it together, you and Jordan. Mr Christie also asked White about his previous criminal convictions. The court heard that White had previously served time in prison for an assault which caused the victim to suffer brain damage. White said he had only been 16 at the time and that it was the worst mistake of his life. He added: I have done my time for that. I pleaded guilty and handed myself into the police. I have changed now. I have grown up. The case continues.