The civil rights lawyer credited with overturning the convictions of the Guildford Four is to give evidence for Roisin McAliskey in a legal battle.
Roisin McAliskey is wanted for questioning in Germany
She is fighting to stop her extradition to Germany over a 1996 bombing.
The daughter of the former MP Bernadette McAliskey is wanted for questioning about an IRA bomb attack on the British army barracks at Osnabruck.
The Recorder's Court in Belfast heard that Gareth Pierce will claim that she suffered abuse while in custody.
Ms McAliskey was arrested at her home at Coalisland, County Tyrone, last month and is out on bail awaiting the outcome of the extradition proceedings.
The German authorities are seeking her extradition for the second time.
The first bid was abandoned in 2000 when the Crown Prosecution Service in England ruled she had no case to answer.
Her solicitor told Wednesday's hearing that Ms Pierce would give evidence that Ms McAliskey was abused by police in Castlereagh holding centre in Belfast and also suffered while in custody in England when she was pregnant.
He said she had been examined by a psychiatrist on 16 June and a further consultation was needed before a full report could be prepared.
The hearing was adjourned until 22 August.