An Iranian intelligence agent charged in the beating death of a photojournalist spent hours interrogating her unsupervised at a prison, a prosecutor said Tuesday.

Mohammad Reza Aghdam Ahmadi (search) pleaded innocent to charges he murdered journalist Zahra Kazemi (search), who suffered fatal head injuries sometime during three days of interrogation after her June 23 detention. She died in a hospital July 10.

Kazemi, 54, who held Canadian and Iranian citizenship, was detained while taking photos outside the Evin (search) prison north of Tehran during student-led protests.

Kazemi's death has become part of the power struggle between the reformist and conservative wings of the Iranian government, and has soured Iran's relations with Canada.

Tehran Deputy Prosecutor General Jafar Reshadati (search) said Tuesday that Ahmadi was the only interrogator who spent long periods of time alone with Kazemi, refused to answer some questions about her treatment and gave contradictory statements.

Reshadati told the court a prison doctor confirmed June 26 that Kazemi was in good health and had responded to questions in writing. Hours later, she was rushed to the hospital with fatal injuries.

"Now, the accused should explain how a healthy person in his control who responded to questions in 18 pages by her own handwriting is then transferred to hospital and finally dies," Reshadati said.

Ahmadi's lawyer, Ghasem Shabani, told the court the indictment was flawed and showed "serious and deep contradictions" with documents provided by the Intelligence Ministry.

Declaring his innocence, Ahmadi said: "I strongly reject the charges raised against me," and requested more time to study the indictment.

Judge Rasoul Ghanimi granted the request, and it was unclear when the trial would resume.

After her interrogation, Kazemi was taken to a hospital controlled by the hard-line Revolutionary Guard (search)s. Prosecutors initially said she died of a stroke, but an investigatory committee appointed by Iran's reformist President Mohammad Khatami later found she died of head injuries sustained in custody.

Ahmadi was one of two Intelligence Ministry (search) agents initially charged in Kazemi's death, but prosecutors dropped the charges against the other agent last month. On Tuesday, Reshadati named five intelligence agents and a judicial agent who were not charged because of lack of evidence.

After Tuesday's court session, Ahmadi's attorney told reporters the Intelligence Ministry has documents Kazemi wrote in prison that discredit Reshadati's arguments. He did not elaborate, but said those points would be part of the defense.

The Intelligence Ministry, which is controlled by reformists, have rejected the indictments of its agents and threatened to "expose all the facts" if the conservative judiciary did not withdraw the charges.

Ministry officials contend a judicial agent beat Kazemi in the head and accused the judge of ignoring evidence proving their claim.

In a statement released Tuesday evening, the Intelligence Ministry said Kazemi, in her writings dated June 24, complained that she was beaten on June 23 by a prison official, who would be from the hard-line judiciary.

The case also has damaged relations between Iran and Canada, whose foreign affairs minister, Bill Graham, accused a hard-line prosecutor of being implicated in the killing, saying agents would not act without orders from above.

Canada threatened sanctions and withdrew its ambassador after the photojournalist's body was buried in her birthplace, the southern Iranian city of Shiraz, against the wishes of Canadian authorities and her son in Montreal.

Canadian Ambassador Philip Mackinnon, who returned to Iran earlier this month, attended the trial Tuesday.

Authorities prevented photographers from entering the courtroom Tuesday, saying they did not want the faces of Intelligence Ministry agents published.