The National Investigation Agency (NIA) has taken over the case involving J&K cop Davinder Singh who was held with militants in south Kashmir while ferrying two militants to Jammu, officials said.
The development comes just days after the Union Home Ministry asked the NIA to initiate the process of probing the case.
Singh, posted as the deputy superintendent of police, was arrested last weekend along with Naveed Babu, self-styled district commander of banned Hizbul Mujahideen, a new recruit Atif and an advocate Irfan Mir.
The four were caught with arms and ammunition while they were travelling in a car near Qazigund on the national highway in south Kashmir.
After receiving orders from the Union Home Ministry, the NIA has re-registered this case and started the investigation, the spokesman said.