"We had sent the LR to the Chicago court (that tried Headley). But, as of now, there is no response from there," said Himanshu Roy, Joint police commissioner (Crime).
"We want to question Headley and Rana, which will help us to establish their local links in Mumbai," he said.
Last year, a team of NIA officials had questioned Headley to derive information about his role in the Mumbai attacks. However, to protect the confidentiality of the investigations, both India and United States did not disclose the contents of the interviews.
Headley has pleaded guilty in the Chicago court on 12 terrorism charges, including his involvement in the 26/11 terror attack.
However, Rana was acquitted by the court of conspiracy to provide material support to the terror attacks. A team of NIA will soon visit United States to question Rana about his material support.