The International Criminal Court on Tuesday threw out the case against Kenyan Deputy President William Ruto.
The presiding judge declared it a mistrial because of a "troubling incidence of witness interference and intolerable political meddling".
Ruto denied murder, deportation and persecution charges during violence that followed the 2007 elections in which about 1,200 people were killed.
His lawyers wanted the case to be terminated due to a lack of evidence.
Ruto was one of the most senior politicians to be tried by the ICC.
In February judges at the ICC barred the use of recanted testimony, meaning that prior recorded witness statements could not be used by prosecutors.
Several key witnesses in the case have changed their statements, which prosecutors said was due to intimidation and bribery.
Ruto's lawyers said he should be acquitted because so many key prosecution witnesses either dropped or changed their original statements.
ICC prosecutor Fatou Bensouda acknowledged that the loss of witnesses weakened the case against the deputy president - but she argued there still remained enough evidence to proceed with the trial.
In 2014, the prosecutor dropped similar charges against Kenyan President Uhuru Kenyatta, alleging that witnesses had been intimidated to make them change their testimony.
Ruto and Kenyatta were on opposite sides of the 2007 election, but formed an alliance that won the 2013 election.
