Peter de la Serpe, who is suspected of involvement in several killings, had been due to give evidence in the trial

Peter de la Serpe, who is suspected of involvement in several killings, had been due to give evidence in the trial of 10 men and one woman charged with at least seven gangland killings.key crown witness in a Dutch gangland trial is refusing to testify because he says he does not trust the police to guarantee his personal safety, the Telegraaf reports on Monday.The Telegraaf reports that De la Serpe, whose evidence is considered vital to the prosecution's case, wants to pull out. According to Nos news, he is not happy about the amount of money he has been promised to build up a new life after the trial. De la Serpe had also threatened to pull out of the trial in January but that dispute was settled, the Nos says.