John Walker Lindh, who is being held in a federal prison in Terre Haute, has won a lawsuit for rights to daily group prayer.
Lindh is suing the US government, saying the prison is stifling his religious freedom.
Attorneys will file post-trial briefs, and the court has no timeline for when the case will be decided.
Wednesday's trial included a closed-door testimony from intelligence analyst.
An imam told the court Tuesday that John Walker Lindh's brand of Islam does not require group prayer.
John Walker Lindh says a Terre Haute prison's prohibition of group prayer violates his religious rights.