THE investigative history of former Deputy Commissioner of Police Mark Shields took centre stage Friday as defence lawyers went on the attack, detailing reprimands by a British court for improper conduct and highlighting his questionable actions in the Crawle murder probe involving retired tough cop Reneto Adams and other accused policemen.

Shields, a former member of Scotland Yard, said he was cleared in a departmental probe of any inappropriate behaviour in London, but at the end of his examination Friday a picture had emerged of an investigator who was willing to operate within grey areas in pursuit of cases.

There was audible reaction from jurors when Shields testified under questioning by Queen's Counsel K Churchill Neita of his actions in the Crawle probe. The policemen in that case were acquitted in December 2005 of the deaths of four civilians in Clarendon.

As Neita continued his grilling of Shields, the former senior cop was cast as a man haunted by his failure to secure a conviction in the Crawle case and the "embarrassment" of the 2007 inquest into the sudden death in Jamaica of Pakistan cricket coach Bob Woolmer.

Shields, the defence charged, wanted to redeem himself with the current murder case in the Home Circuit Court in which three policemen are charged in connection with the deaths of Kemar Walters and Oliver Duncan in 2004.

"I'm suggesting that this was your opportunity to leave on a high note and that is why you pushed this case the way you did. You were seeking redemption, Mr Shields," Neita said.

"No," responded Shields, who later insisted that the Bob Woolmer case wasn't a source of embarrassment for him. "To the contrary," he said.

As Shields was being pulled through the wringer, Adams, a retired senior superintendent, sat among the spectators looking pleased.

Both men have a history of taking swipes at each other as Adams is of the view that Shields' secondment to Jamaica didn't benefit the country, while Shields has openly criticised Adams' rough style of policing.

Assistant Superintendent Victor Barrett, Corporal Louie Lynch and Constable Paul Edwards are on trial for the murders of Kemar Walters and Oliver Duncan who were abducted from the Washington Plaza off Washington Boulevard, in St Andrew on December 23, 2004.

The prosecution is claiming that there was a conspiracy between Lynch and Edwards to kill both men and that Barrett covered up the crime.

The defence is claiming that the men are being wrongfully prosecuted.

On Friday, Valerie Neita-Robertson (Lynch's attorney) was the first to delve into Shields' past investigative conduct, bringing up his two-time reprimand by the British Court of Appeal.

Neita-Robertson set up this aspect of her cross-examination by pointing out discrepancies between a recorded interview that Shields conducted with the prosecution's main witness and the subsequent statement that was made from the interview.

The discrepancies had to do with the time of day certain things were said to have happened as they relate to Walter's and Duncan's abduction.

Shields was accused of leading the main witness as to the time of the events because he was in possession of call data that showed specific times which he wanted to fit into the witness' statement.

Shields denied this, but Neita-Robertson pressed on.

"That's not unusual for you, Mr Shields, to trespass over the line of propriety?" she asked.

"No," Shields said in disagreement.

With this, Neita-Robertson put to him, and he agreed, that a British judge had remanded him about "trespassing over the line of propriety".

"That was the judge's view," Shields added.

He also denied that he had briefed four witnesses in each other's presence. Pressed further, Shields said the judge did write a judgement accusing him of "improper conduct" in that he had briefed the four witnesses in the way he's accused of doing.

He said it was the judge's view that his conduct gave the "witnesses of fact an advantage".

He also agreed that he had told the judge who had reprimanded him that he did not see anything wrong with what he had done.

Additionally, Shields said he recalled being involved in a case in which the British Court of Appeal said it was satisfied that observation logs provided by him, after the fact, had been fabricated.

But Shields said he was cleared of any wrongdoing following an internal review that was conducted because of the judge's reprimand.

Neita was next to cross-examine Shields. Among other things, Shields said he visited Barrett in lock-up and told him that he knew he did not commit the murders.

Shields denied, however, that he told Barrett to think about his career and come on his side.

"Didn't he tell you that the only thing he knew is what he read in the newspaper?" Neita asked.

"I don't know," Shields said.

Shields also denied that Barrett told him that he would not tell lies on his colleagues.

"Didn't you tell Mr Barrett that there were two doors, one to freedom and one to prison?" Neita asked.

But Shields denied this, leading Neita to bring up the Crawle case. Shields told jurors on Friday that he had testified in the Crawle case of telling one of the accused cops, Roderick Collier, to join him and avoid prosecution.

Neita asked: "Didn't you do the same thing with Mr Barrett as you did with Mr Collier?"

"No, sir," Shields said. "Different case, different circumstances."

Some of the 12 jurors gasped and commented as Shields admitted to giving a police officer a telephone in the Crawle case and asking him to get an admission from Adams that could strengthen the case.

Shields said that the cop's conversation with Adams was recorded.

Shields also denied that he offered not to charge Barrett if he resigned from the Jamaica Constabulary Force.

The case continues today with a new witness.