The United Progressive Alliance government will bring a constitutional amendment Bill to create the much-anticipated Federal Investigative Agency. Top sources of the government suggest that the constitutional amendment route will provide a one-window solution to modify the various laws related in creation of the federal agency.

"Some powers of the state police have to be taken over by the proposed central agency to function. This will require changes in state laws and also some central laws. If we go for a constitutional amendment, the Bill can take care of all related changes," said a top UPA minister.

Initially, the government had planned to create the federal agency to curb internal security problems through an executive order. But now, as the main Opposition parties like the BJP and the CPI-M have given their nod along with the allies like the RJD or SP, the government is mulling the creation of an agency through an act of Parliament to make it more effective.

"Formation through an executive order not only would have diminished its effectiveness but its validity also would have been challenged in the higher courts," said a top leader.

On Sunday evening, the UPA managed to reach to a political consensus to make a federal agency at an all-party meeting convened by the prime minister.

The Veerappa Moily-led Administrative Reforms Commission had in a report on public order advocated a similar federal investigating agency for dealing with cases with inter state and national ramifications.

According to the new law he had recommended to set up such an agency, federal crimes would have included organised crime, terrorism, acts threatening national security, trafficking in arms and human beings, sedition, major crimes with inter-state ramifications, assassination of major public figures and serious economic offences.

These would have been withdrawn from the jurisdiction of state police.

Justifying the need for a separate law and a separate authority to deal with "federal crimes" the report said that increasingly major crimes like terrorism, arms trafficking have inter-state and international ramifications and threaten national security. It says that though criminal law is in the concurrent list, police are in the state list. And hence state police investigates all major crimes.

It says that though the Central Bureau of Investigation is there to look at cases nationally, it can investigate criminal cases only with the consent of states. It points out that states and their police whose jurisdiction is confined to state borders often confront difficulty in carrying out investigations across borders. Again, the state police are often overburdened and hence the need for creating a "specialised federal agency".