Donna Maguire, Sean Hick and Paul Hughes are accused of acting in concert to murder Major Michael Dillon-Lee, who was shot outside his home in Dortmund in June 1990.
They are also accused of attempted murder in connection with a failed attempt to bomb a Rhine Army barracks in Hanover in May 1990. A second count of attempted murder relates to shots fired at police as Major Dillon- Lee's killers fled.
Mr Hick, 32, of Dublin, and Mr Hughes, 29, of Newry, Co Down, have pleaded not guilty and deny being members of the Provisional IRA. Ms Maguire, 26, of Newry, has yet to plead.
At the trial, in Dusseldorf, it will be claimed that the three were members of a five-strong IRA active service unit set up on the continent in early 1990.
Gerard Harte, still sought by the German police, is alleged to have been another member. Desmond Grew, shot dead by the security forces in Northern Ireland in October 1990, is said to have been the fifth.
Last year Ms Maguire, Mr Hick and Mr Hughes, together with Mr Harte, were acquitted by a Dutch court of killing two Australian tourists in Roermond in May 1990 after mistaking them for off-duty British servicemen.Reuse content