Four Iranian brothers who were detained for more than three years after the 2001 terrorist attacks filed a lawsuit Monday in federal court, claiming they were held on false pretenses during an FBI investigation.

The brothers' attorney said they "were detained longer than virtually all of the post-Sept. 11 detainees caught up in the sweeps of non-citizens." The four were released from custody in March 2005.

Attorney Paul Hoffman said the only reason for the brothers' detention was that they took part in rallies protesting the current Iranian regime.

The lawsuit named former Attorney General John Ashcroft, FBI Director Robert Mueller and other federal officials as defendants.

Thom Mrozek, a spokesman for the U.S. attorney's office, declined to comment because authorities had not seen the complaint.

The lawsuit alleges that the brothers were held in inhumane conditions, were denied basic medical care and were "subjected to vicious attacks by guards and other inmates."

Hoffman said the brothers — Mohammed, Mostafa, Mohsen and Mojtaba Mirmehdi — were detained in October 2001 because their names were on a list of people who attended a rally in Denver protesting the Iranian regime. They were alleged then to have ties to the Mujahedin-e Khalq, a group also known as MEK that was deemed a terrorist organization by the State Department.

"But none of the brothers was a member or supporter of the MEK, as government officials knew when the brothers were detained," Hoffman said.

The government tried to deport at least two of the brothers, but Hoffman said that was barred by a court finding that they would be tortured or killed if they returned to Iran, the country they fled after being imprisoned there for political protests. Two of them were denied applications for asylum in the United States and two other applications are still pending, Hoffman said.

Since their release last year, the brothers have returned to their real estate business in the San Fernando Valley, he said.