Zahra Kazemi, a photographer of Iranian origin, died in July 2003, two weeks after being detained for taking photographs outside a Tehran prison during student-led protests against Iran's ruling establishment.
Kazemi's case had drawn fresh international attention to reports of Iranian human rights abuses and conditions inside the country's prisons. It also prompted Canada last week to announce the withdrawal of its ambassador in Tehran.
The court's move yesterday to end the trial prompted outrage from Kazemi's legal team, headed by Nobel Peace Prize winner Shirin Ebadi.
Ebadi accused the judiciary of a cover-up by pinning blame on a single intelligence agent -- Mohammad Reza Ahmadi -- and disregarding evidence that judiciary officials may have been involved in the murder.
"I don't accept this court! We don't accept this court! This court is not acceptable! The proceedings were declared over. As a sign of protest, the mother of Zahra Kazemi and we, the lawyers, together have left the court," Ebadi said.
Ebadi's legal team claims the accused is innocent and is being used as a scapegoat.
The court met only three times in the trial of intelligence agent Ahmadi, who pleaded innocent on 17 July to charges of "semi-intentional murder." Reports say a verdict may be handed down within a week.
Iranian authorities initially claimed Kazemi died naturally of a stroke. Later, a committee appointed by President Mohammad Khatami found that Kazemi had died of a fractured skull and brain hemorrhage from a blow to the head.
Kazemi's mother tearfully accused Iranian officials of torturing her daughter to death.
Ezzat Kazemi told the court that there were burns on her daughter's chest and fingers and that her nose and toes were broken.
Ebadi's legal team accuses a prison official of inflicting the fatal blow. That official has been cleared of any wrongdoing. Ebadi's team accused the court of ignoring testimony that might have incriminated him.
In a news conference yesterday, Ebadi threatened to take the case to an international court if Iranian justice provides no further avenues to pursue it.
Mohammed Seyfzadeh, part of Ebadi's legal team, told RFE/RL that he believes Iranian officials will be compelled by law to return the case to a higher court.
"I'm saying this based on the law: They have no choice than to return the case to the primary court because of the many offenses that have been committed in this case," Seyfzadeh said.
The decision to end the trial was denounced by the Paris-based Reporters Without Borders as a "denial of justice."
The European Union also expressed concern over the trial and deplored the barring of EU diplomats from the trial's final session, which was closed to foreign journalists as well.
(RFE/RL's Radio Farda contributed to this report.)