Amin, a suspended Deputy Superintendent of Police, was arrested yesterday.
"I was severely beaten up and also verbally abused by the CBI officers in custody," Amin accused when he was produced before a Special CBI Judge.
Amin, granted bail on medical grounds by the Bombay High Court last month in the Sohrabuddin Sheikh encounter case, was apprehended from the city's Civil Hospital, where he had been admitted.
However, following Amin's complaint, Judge S H Khutwad, while reserving order on the remand application, asked CBI to take the accused for a medical check-up.
More From This Section
A decision on the remand plea will be given tomorrow.
On June 15, 2004, Ishrat, along with Javed Shaikh alias Pranesh Pillai, Amjadali Akbarali Rana and Zeeshan Johar, was killed in an encounter by Ahmedabad Crime Branch.
Police had then claimed that all four were terrorists who entered the city to kill Chief Minister Narendra Modi.
At the time of the encounter, Amin was serving in the Crime Branch. As per Gujarat police's version, he was part of the team which cordoned off the area near the encounter spot and also took part in the gunfight.
CBI, seeking Amin's custody, submitted "the details of widespread conspiracy to kill the deceased persons and the role played by each conspirator are yet not fully known. The accused person (Amin) knows these details and he has to be interrogated to gather necessary facts.