A plea agreement has been reached with a witness in the trial against four men suspected of terrorist ties.

Yousef Hmimssa, a key witness for the prosecution, has reached a plea agreement with the government, Local 4 reported.

Details of the deal with Hmimssa are expected to be released later this week when he takes the stand, according to reports.

Karim Koubriti, 24, Ahmed Hannan, 34, Farouk Ali-Haimoud, 22, and Abdel-Ilah Elmardoudi, 37, (pictured, left) are charged with conspiracy to provide material support or resources to terrorists.

Defense attorneys argued to the Detroit federal courtroom that the men came to the United States to live the American dream, but ended up in the wrong place at the wrong time.

Prosecutors believe the suspects were organizing a terror plot, and sending money overseas to support terrorist activity, Local 4 reported.

Hmimssa is expected to testify that the men were plotting attacks at popular vacation spots such as Walt Disney World and Las Vegas, Local 4 reported.

FBI Special Agent Mary Ann Manescu told the courtroom Monday that drawings of airplanes immediately caught her attention as she flipped through a day planner found in an apartment where three of the four men lived.

She added that the day planner also contained a sketch (pictured, below) that the government claims illustrates planes, a runway and a bunker at a United States air base.

Defense attorneys said the day planner belonged to a former occupant of the home who was mentally ill and had committed suicide. They argued that the prosecution's witness is a career criminal looking for an early release from prison.

A jury of 12 women and four men will determine if the evidence links the suspects to involvement in a terrorist plot.

It's the first trial in the United States for an alleged terror cell detected after the Sept. 11, 2001, attacks.