The Supreme Court on Thursday ordered Kerala Police to set up a Special Investigation Team (SIT) to probe into allegations of wife-swapping lodged by the estranged wife of a naval officer. The top court, which ruled out the CBI investigation into the First Information Report or FIR alleging that besides the husband of the woman, four other Navy officers and a spouse of one of them were indulged in wife-swapping in the force, directed the Kerala DGP to set up the SIT headed by a police officer not below the rank of a DIG and conclude the probe in the 2013 FIR "preferably" within three months. A bench of Chief Justice TS Thakur and justices R Banumathi and UU Lalit, while rejecting the plea for the CBI probe, said, "It is well settled that the extraordinary power of the constitutional courts in directing the CBI to conduct investigation in a case must be exercised rarely in exceptional circumstances, especially, when there is lack of confidence in the investigating agency or in the national interest and for doing complete justice in the matter."

Justice Banumathi, penning the verdict, said, "Considering the facts and circumstances of the case in hand, in the light of ...principles, we are of the view that the case in hand does not entail a direction for transferring the investigation from the state police/special team of state police officers to the CBI. The facts and circumstances in which the offence is alleged to have been committed can be better investigated into by state police."

It also rejected the submission of the estranged wife of the navy officer that the cases, filed by accused including other naval officers in the Kerala High Court seeking quashing of the FIR, be transferred to the Delhi High Court.

The top court also said that it transfers a case from one state to another only if there is a "reasonable apprehension on the part of a party to a case that justice will not be done".

The petitioner had married the naval office on November 9, 2012. After their marriage, the couple moved to Kochi and within a year they started having problems. She accused her husband of forcing him to attend wife-swapping parties.

The woman first lodged a complaint against her husband, her parents-in-law and sister-in-law accusing them of mental cruelty and torture. She later filed a case of sexual assault against five naval officers, including her husband, and wife of one of the naval officers.

In September 2013, the case was taken to Supreme Court which issued notices to the Kerala government, the commander of Southern Naval Command, her husband and five other officers.