At the ongoing trial of Kenya’s deputy president, William Ruto, and former radio journalist Joshua arap Sang at the International Criminal Court (ICC), the drill is now well established. When the court decides to protect the identity of a witness, a screen goes down on the public gallery; if there is a risk that the testimony will expose the identity of the witness, the proceedings are entirely closed. If the session remains open to the public via video, the face of the witness is disguised with pixelation, the voice distorted.

So far all but one of the 13 witnesses at the Ruto and Sang trial, which opened on September 10, 2013, has taken the stand with their identity cloaked from the public, as the court examines accusations that the two men were responsible for crimes against humanity during the violence that nearly tore Kenya apart in the aftermath of the disputed 2007 presidential election.

The extent to which the ICC has used what it calls “protection measures” in this case reflects the fraught political background in Kenya—at the start of the trial, an attempt was made to reveal the identity of the court’s second witness, potentially exposing the witness to the threat of retribution, as the court noted at the time. In addition, the prosecution says seven of its witnesses have withdrawn from the case, possibly as a result of being either bribed or intimidated. In the related case against President Uhuru Kenyatta, which has yet to be heard in court, seven witnesses have been withdrawn by the prosecutor in the past year, at least two specifically for safety reasons.

Some in Kenya have claimed that these steps to protect the identity of witnesses are unfair to the defendants. Ahmednasir Abdullahi, a Nairobi-based lawyer who is an outspoken critic of the Kenya cases and the ICC in general, complained in September, on the website of the Daily Nation, that “closing sessions during cross examination of protected witnesses is “unfair”: “It is grossly prejudicial that when they [the defendants] come to confront their accusers in court, the judges switch off the lights.”

At the ICC, Article 68(1) of the Rome Statute sets out the court’s general responsibilities: namely to “take appropriate measures to protect the safety, physical and psychological well-being, dignity and privacy of victims and witnesses.”

However, the use of measures to shield the identity of witnesses is not unique to the Kenya trial now underway at the ICC. Such steps are standard procedure in international tribunals trying grave crimes, as well as national courts, including U.S. federal courts, and under English law.

At the International Criminal Tribunal for the Former Yugoslavia (ICTY), Rules 69 and 75 of the Rules of Procedure and Evidence allow the court to employ wide range of protective measures, including expunging names from the tribunal’s public records, non-disclosure to the public of any records identifying the victim, or give testimony through image of voice or face distortion or testify under pseudonym, to ensure safety and well-being of the witnesses.

The ICTY has heard from more than 4,500 witnesses since its first trial in 1996. About a quarter of these witnesses testified with some type of protective measure. At the International Criminal Tribunal for Rwanda (ICTR), over 80 per cent of more than 3,400 witnesses were covered by protective measures, which in some cases included relocation. The Special Court for Sierra Leone used similar rigorous measures to protect witnesses; and the Extraordinary Chambers in the Courts of Cambodia has also has legal protections available.

In the first ICC prosecutions against Thomas Lubanga, Jean-Pierre Bemba, and Mathieu Ngudjolo and Germain Katanga, the chambers routinely applied protective measures, again reflecting a situation where political factors at home – in these cases continued instability – could jeopardize the safety of a witness.

In the Ruto and Sang case, after the attempt to identify the first witness in September, the judges issued a stern warning to all parties that leaking names of witnesses and engaging in behavior that negatively influences the witnesses will not be tolerated. Judge Chile Eboe-Osuji stressed that “any revelation of the identity of a witness whose identity has been protected by this Court amounts to an offence in [the ICC].  So too will any attempt to engage in any such revelation.”

Subsequently, the prosecutors requested to issue an arrest warrant for charges of interference with witnesses testifying against Ruto and Sang. Walter Osapiri Barasa, a Kenyan journalist, was charged with three counts of bribing and attempting to bribe three witnesses.

Similarly, a month after the ICC issued an arrest warrant for Barasa, the court issued five arrest warrants in connection with the prosecution of Jean-Pierre Bemba, accusing them of attempting to bribe witnesses. All the suspects in the Bemba case have been handed over to the ICC, while Kenya’s High Court has ruled Barasa can be extradited from Kenya to the ICC.

The issuance of arrest warrants on charges of offences against the administration of justice shows the prosecutor is taking the charges of witness intimidation seriously. It also reaffirms the importance of the court in ensuring protection and safety of witnesses whom continue to provide essential evidence to successfully prosecute the perpetrators.