Mr Peter Ngugi Kamau whose confessions in the murder of lawyer Willie Kimani police want to use in the trial has revealed that he had been a police informer and used to spy on their behalf since 2009.
He said when police picked him up on August 8, 2016, he thought they were seeking his services. As an informer, he would be paid good money, depending on the amount of work, he said.
However, things changed when lawyer Kimani was murdered.
The accused said he was picked up at Waithaka bus stop in Dagoretti and taken to Kiambu where he was interrogated for hours.
Among the police officers who picked him up were Mr Clement Mwangi, whom he described as a friend, and Mr Nicholas ole Sena.
Mr Ngugi denied making the confession, which the prosecution wants to rely on in the trial, stating that he does not understand English and he was given papers on which he placed his thumbprint.
The accused told the court that he refused to cooperate with the police officers this time round because they had not to pay him for a previous job.
He said after the arrest, he was kept in a safe house for about three weeks as they promised to use him as a prosecution witness.
He said while in the safe house, the officers treated him well; feeding him chicken and roasted meat as well as a packet of cigarettes daily.