Orders to falsify a Toni Yengeni drunken driving docket came from Western Cape police commissioner Mzwandile Petros, the Parow Regional Court heard on Thursday.
Petros's alleged instructions were passed down to former Goodwood police station commander Siphiwo Hewana.
"When Hewana told me in his office that the instructions came from the provincial commissioner himself, there was not much for me to say," Constable Jeremy Voskuil told the court.
Hewana is alleged to have unlawfully ordered the two police constables involved in the investigation to falsify the docket of Yengeni, a former ANC chief whip.
Hewana is charged with attempting to defeat the ends of justice, incitement to commit perjury and interfering with the Yengeni drunken driving investigation. Because of the charges, Hewana was dismissed as the commander at the Goodwood police station.
He has pleaded not guilty to all charges.
Voskuil said on Thursday: "I told him (Hewana) it was not going to work, and that it will all come out, but he said not to worry and that nothing will ever happen to us."
The second investigator was Constable Charles Japhta.
The false alteration to the docket involved the time of Yengeni's arrest.
Prior to the incident, Yengeni was released from prison on parole after serving time for fraud.
Two of his parole conditions were that he was not allowed to be out on the streets after 10pm, or consume liquor whilst on parole.
Any violations of the conditions would have put an end to Yengeni's parole.
Japhta told the court they had pulled Yengeni off the road in the early hours of Monday, November 27, 2007, and that the correct time of arrest had been noted in the docket.
However, he was later ordered by Hewana to change the time of arrest to 9am the preceding Sunday.
Voskuil testified that he and Japhta were summoned to Hewana's office at about 10pm on the day after the arrest.
Hewana said he had had people telephoning or coming to see him all day about the Yengeni arrest, and it was "causing a lot of trouble for everyone".
Voskuil added: "Hewana said we must remember that the provincial commissioner and other senior officers were all former ANC cadres, and none of them wanted to see Yengeni go back to jail.
"Hewana warned us that if Yengeni went down, we would go down with him.
"He said we must think about it, as it involved our families and our future in the police, and that we would one day be remembered as the people who had sent Yengeni back to jail."
Yengeni has since been acquitted on the drunk driving charge.
The trial continues. - Sapa