A taxi driver who detectives thought had information about Lynette White’s murder was warned “to keep his mouth shut”, a court heard.
Three innocent men, known as the Cardiff Three, were jailed for the murder but were later freed on appeal.
Jack Ellis was named in statements claiming to have been outside White’s James Street home in the early hours of 14 February 1988.
The prosecution at Swansea Crown Court argue the statements are false.
Eight ex-police officers deny conspiracy to pervert the course of justice.
Two other people deny perjury.
Ellis told how he was put under pressure to admit he was there and to name the people in his cab.
He said he stuck to his true account and refused to give in. He said he could remember the fares he had carried that night and he had not been in James Street.
It is alleged that the attempt to “brow beat” Ellis was an example of how officers tried to manipulate witnesses into providing evidence.
The trial continues.