Congolese former vice president Jean-Pierre Bemba and his defence team bribed witnesses to lie in his favour at a war crimes trial that ended in the highest ranking conviction by the International Criminal Court, judges ruled on Wednesday.

The court said 14 key witnesses had been coached about what to say, and found Bemba and four other defendants guilty of conspiring to present false evidence to the court.

Supporters of Bemba, who is appealing his conviction and 18-year sentence for overseeing a campaign of rape and murder in Central African Republic more than a decade ago, had no immediate comment.

When they found him guilty in March this year, judges ruled the politician, who served as vice president from 2003 to 2006, failed to discipline or restrain his Movement for the Liberation of Congo (MLC) soldiers as they rampaged through the neighbouring country in 2002 and 2003.

As part of a systematic effort to interfere with the trial, Bemba and his team used secret phones and code language to instruct witnesses in exchange for cash, promises of relocation, computers and other bribes, the court found.

“No legal system in the world can accept the bribing of witnesses, the inducement of witnesses to lie, or the illicit coaching of witnesses, nor can the International Criminal Court,” Presiding Judge Bertram Schmitt said.

“Today’s judgment sends the clear message that the court is not willing to allow its proceedings to be hampered or destroyed.”

Those convicted face sentences of up to five years, or a fine, or both.

Schmitt allowed suspects other than Bemba to remain free pending their sentencing hearings, for which he did not set a date, saying they had cooperated with the court and were not considered a flight risk.

The four others convicted include Jean-Jacques Mangenda Kabongo, a member of Bemba’s legal team; and Fidele Babala Wandu, a politician and close associate of Bemba.