University of Zimbabwe law professor Welshman Ncube has been charged with high treason by police investigating an alleged plot to assassinate the president, Robert Mugabe.
Professor Ncube is secretary-general of the Movement for Democratic Change, whose leader, Morgan Tsvangirai, has already been charged. Both men and a third MDC MP have denied the charge and have been released.
Professor Ncube said: "The allegations are nothing but yet another Zanu PF trick to tarnish the image of the MDC."
The charges arise from a videotape that purports to show Mr Tsvangirai discussing the elimination of Mr Mugabe with a political consultant. Mr Tsvangerai said the charges were fabricated to try to remove him from the political scene in advance of elections on March 9 and 10.
• A Harare inquest this week into the death of a student, Batanai Hadzizi, found the police to be responsible for his "thoroughly brutal" slaying. The magistrate ordered the police to open a murder docket, which must be completed by the end of May.
Jacob Mafume, of the Harare law firm Kantor and Immelman, said: "At last we have official support for what students at the university have been saying all along.
"It is not they who are out to disturb the peace, but the police who are brutalising students at every opportunity they get. This is the first step towards bringing the perpetrators of such brutalisation against students to justice."
Mr Hadzizi was killed by police who had been called on to campus to quell one of several protests last year. Vice-chancellor Graham Hill told The THES this week: "I am not aware of the police being called by the university during student demonstrations."
He added: "There is total academic freedom on campus. The university has no objection to student demonstrations that are peaceful and do not infringe on the rights of other students and disrupt the academic timetable of the university."