Shaikh was produced before Additional Sessions Judge Reetesh Singh after expiry of his police custody and Special Cell of Delhi Police sought extension of his remand by 20 more days saying investigation in the case was on.
The police told the court that they were in the process of analysing the call detail records of the mobile phones and SIM cards recovered from the possession of the accused.
27-year-old Shaikh, brother-in-law of Pakistan-based absconding top IM operative Mohsin Chaudhary, was earlier sent to 10 days' police custody by the court.
Shaikh, a resident of Pune in Maharashtra, was arrested by special cell from Saharanpur in Uttar Pradesh on the basis of a tip-off.
Police earlier claimed Shaikh had disclosed he "is an active member of IM and had been involved in several terrorist activities of the outfit for the past several years".