Four top SIMI activists including its Madhya Pradesh chief Safdar Nagori, arrested on March 27 from Indore, were brought to the city from Mumbai amidst tight security.
Nagori, Qamarudding Nagori, Hafiz Hussain alias Adnan and P A Shivli were among the 13 activists of the banned outfit rounded up four months ago.
They were initially sent to police custody for interrogation. Later all the 13 SIMI men were remanded in judicial custody and sent to Central Jail in Indore.
The four were taken to the financial capital on a production warrant in connection with the probe into the July 11, 2006 train bombings in Mumbai.
According to sources, the four activists were handed over to Maharashtra's Anti-Terrorism Squad (ATS) by the prison administration recently and kept at Mumbai's Arthur Road Jail.
They were brought to Mumbai on Wednesday night by an 11-member ATS team of Mumbai Police.