A decision in the case of five American suspects facing trial in Pakistan on terrorism charges is expected within one month, the suspects' defense attorney told CNN Tuesday.

Barrister Hassan Dastgir Katchela, who represents all five of the young men, explained that three of the remaining eight prosecution witnesses were cross-examined by the defense Tuesday in court.

The trial for the suspects, who are accused of plotting attacks against Pakistan, began March 31.

The Americans face sentences of up to life in prison if convicted, but their lawyers claim they planned no such terror attacks and were implicated by Pakistani authorities who were under intense pressure to indict them.

The prosecution had a total of 23 witnesses, he said. Fifteen of them had been questioned in previous hearings, Katchela added.

In court Tuesday, the defense cross-examined Mazhar Abbas, who is in charge of cyber crimes in the city of Sargodha, where the men were arrested. Also appearing Tuesday were Malik Usman, a police official who led the operation against the suspects and allegedly recovered maps of nuclear facilities and Jihadi literature, and Nazir Ahmed, an investigator in the case.

The accused men, who have been called the "D.C. 5" because they all lived in the region around the U.S. capital, have been charged with several terrorism-related counts including criminal conspiracy to commit terrorism and waging war against Pakistan and its allies, including the United States.

The five Americans - Ahmed Abdullah Minni, Umar Farooq, Aman Hassan Yemer, Waqar Hussain Khan and Ramy Zamzam - used to worship together at a mosque in Alexandria, Virginia, until they went missing in November and turned up in Pakistan. They were arrested in December in Sargodha, about 120 miles south of Islamabad, after their parents in the United States reported them missing.

Andrea Hiller, from the U.S. Embassy, has attended all the court sessions in the trial, Katchela said.

The next hearing for the men is May 6, their attorney said.

- Journalist Nasir Habib contributed to this report.