New Delhi: A day after former Gujarat Home Minister and Narendra Modi's key aide Amit Shah was arrested, questions are now being raised over why the CBI, which Shah, did not seek his immediate custody?

The BJP says since the investigating agency did not have any substantial evidence, it couldn't apply for custody. But the CBI on its part asserts that they would approach the court for custody in a week's time.

Right now their priority is to meet the Supreme Court deadline on the action-taken report which is to be submitted to the apex court on July 30, CBI sources said.

The agency is also planning to collect some more statements including the marble traders of Rajasthan before they confront Shah with enough evidence.

Shah was arrested by the CBI in the Sohrabuddin Sheikh fake encounter case on Sunday. He was taken to CBI judge A Y Dave's house, who remanded him to 13 days in judicial custody. (Watch: Shah quit out of respect for law, says BJP)

The former Gujarat Home Minister will spend the next two weeks in Sabarmati Jail, but can appeal for bail.

Shah has been charged with murder by the CBI. He was missing since Thursday and had not appeared when summoned repeatedly by the CBI for questioning. (Watch: Amit Shah - the insider)

He had sent in his resignation letter to Chief Minister Narendra Modi on Saturday. The letter was forwarded to the Governor. (Read: Gujarat minister Amit Shah resigns, Modi says Shah is not guilty)

Tags: Amit Shah, BJP, CBI, Gujarat, Narendra Modi