Detective Sergeant Christopher Crowley also tried to thwart the investigation of an earlier racist killing in the area, again by discrediting the key prosecution witness, it was alleged at the public inquiry into Stephen's death.
The case brought by Stephen's parents in 1995 was abandoned after the trial judge ruled out identification evidence by Duwayne Brooks, Stephen's friend who was with him when he was stabbed to death by a white gang in Eltham, south-east London, in 1993. DS Crowley's account of a conversation with Duwayne after an identification parade was a crucial factor that led to the judge's decision. He claimed Duwayne told him that friends had primed him to pick out a suspect.
Cross-examined yesterday by Ian McDonald QC, counsel for Duwayne, DS Crowley denied having any connection with the families of five youths later charged with killing Stephen. He said he had heard of Clifford Norris, the father of one suspect, who was described by Mr McDonald as "a well- known south London villain involved in drug trafficking and firearms". But he only knew his name and had had no dealings with him or his associates, he said.
"Did you know he was someone known to buy off witnesses and jurors?" asked Mr McDonald. "No, I didn't," DS Crowley replied. "Did you ever hear rumours of him buying off police officers?" "No."
Mr McDonald alleged that in the case of Rolan Adams, a black teenager murdered by a white gang in February 1991, DS Crowley's actions had demolished the credibility of Rolan's brother, Nathan, who was the principal witness.
He arrested Nathan twice for alleged offences, Mr Mcdonald said, an assault and a robbery. In the case of the assault, another juvenile was also arrested. Both exercised their right to silence, but only Nathan was charged. He told DS Crowley: "Your questionable involvement in both murder inquiries, if unexplained, is sufficiently serious that it provides a basis for inferring an attempt to thwart the success of both inquiries."
The public inquiry was told that DS Crowley was not involved with the Lawrence investigation, but was assigned to escort Duwayne to an identification parade in Southwark. After the parade, in which Duwayne identified Luke Knight, one of the five, he allegedly asked DS Crowley if he had picked the right one. He also, according to the detective, said he believed he had pointed out the brother of Neil Acourt, whom he had identified on an earlier parade.
DS Crowley said yesterday that he stood by his account of the conversation, key details of which are denied by Duwayne. He said Duwayne told him that he had not seen the faces of Stephen's attackers, and friends had given him a physical description of Acourt's brother before the parade.
The inquiry continues today.