The newly-constituted National Investigation Agency, which was created in the wake of Mumbai terror attacks, is unlikely to probe any of the cases related to the country's most audacious terror strike.

"The investigations into the Mumbai terror attack are being conducted by Mumbai Crime Branch and they have unearthed almost everything. There is nothing much left to probe by the NIA," a top Home Ministry official said.

The Mumbai Crime Branch, which is probing the terror attacks by examining and verifying different angles of the cases, including intercepts of conversation between the terrorists and their handlers across the borders, may file the chargesheet by January end.

"Like CBI, NIA will have no problem in taking over even the old cases for investigation if probe into that particular case has not made much progress," the official said.

There are many terror-related cases in different parts of India, which are yet to be completed due to various reasons, including want of evidence, and needed to be probed thoroughly.

"The Mumbai Crime Branch has also initiated the process of getting the Black and Blue Corner Interpol notices issued in the names of the terrorists through CBI," another official said.

The Black Corner Notices are issued so that people come forward and claim bodies and Blue Corner Notices are issued to check if the person has a criminal record in other countries.

The NIA will have concurrent jurisdiction which empowers the central government to probe terror attacks in any part of the country, covering offences including challenge to country's sovereignty and integrity, bomb blasts, hijacking of aircraft and ships and attacks on nuclear installations.

The Bill for setting up the Agency was passed by Parliament in the just concluded session and President Pratibha Patil [Images] has given her assent to the Bill on Wednesday.

The Union Home Ministry issued a formal notification on Thursday paving the way for the constitution of the agency. The agency will probe such incidents which are found to have complex inter-state and international linkages and possible connection with other activities like smuggling of arms and drugs, pushing in and circulation of fake Indian currency and infiltration across the borders.

The NIA has deterrent provisions like detention without bail for up to 180 days and enhanced penalty of life imprisonment for those involved in terror acts.

The measure came against the backdrop of Mumbai terror attacks [Images] and demands for tough anti-terror laws and provides for constitution of special courts to try offences under the NIA Bill and to provide for summary trial.