The prosecution did its best to undermine the credibility of the witness.

原告竭力削弱证人的可信性。

《牛津词典》

Andrew Adams's conviction was reversed because his lawyers had failed to make use of material that would have undermined the sole prosecution witness.

安德鲁·亚当斯的律师未能充分利用可能削弱唯一原告证人证词的材料，因此定罪被撤销。

youdao

Therefore, how to turn the participants of crimes into witness of public prosecution is very important.

因此，怎样使犯罪参与者变为公诉方的证人便显得十分重要。

youdao

But,on Thursday, the 61-year-old Taylor rejected the allegations of a prosecution witness who said Taylor had transported arms to Sierra Leone by road.

VOA: standard.2009.07.31

Mr.Taylor is the first witness in his defense and has spent much of the last 13 weeks dismissing the prosecution case against him as a series of lies.

VOA: standard.2009.11.10

During the trial the testimony of the key witness for the prosecution (who had cut a deal with the government for less jail time in return for pointing a finger at a higher-up like Tobin) was effectively impeached.

FORBES: Magazine Article

QC whose annihilation of the chief prosecution witness in the recent Damilola Taylor murder trial probably qualifies him as one of Mr Blunkett's meddlesome lawyers says that his profession has been seized upon as a convenient scapegoat.

ECONOMIST: Criminal justice

The court heard that concerns about the credibility of the key prosecution witness were not disclosed to the defence.

BBC: Kevin Nunes killing: Five cleared at appeal court