Spain ? Defense attorneys for an Egyptian accused of masterminding the 2004 Madrid train bombings and a Moroccan who allegedly planted the explosives demanded their acquittals Monday, the last day of trial for 28 people charged in the terror attacks.

The attorneys were the last to make closing arguments in the four-month trial, Europe’s biggest terrorism court case. Prosecutors say a homegrown cell of Islamic terrorists staged the attacks in retaliation for the presence of Spanish troops in Iraq.

A defense attorney said prosecutors were trying to convict Rabei Osman, one of three people charged with orchestrating the attacks, “based on nothing, and with an astounding frivolousness.”

Osman, an Egyptian, was arrested in June 2004 in Italy. The main evidence against him was wiretapped conversations in which Osman allegedly tells an associate in Italy the attacks were his idea. He has repeatedly denied it was his voice in the calls.

Ten bombs ripped through four packed commuter trains on March 11, 2004, killing 191 people and injuring more than 1,800.