New Delhi, May 11 : A blue notice has been issued against the US-based gangster, Harjot Singh on the basis of a request by NIA, sources said on Thursday. The notice was issued last month. The blue notice is often issued to collect additional information about a criminal. The NIA has already issued a look out circulars against Amrik Singh and Mandeep Singh hiding in Philippines; Satnam Singh alias Satta, a member of Jagdeep Singh alias Jaggu Bhagwanpuria gang hiding in Greece; and a few more gangsters who are reportedly hiding in these three countries. The NIA wants to identify their exact location to initiate the extradition proceedings. The Special NIA court in Delhi had issued non-bailable warrants (NBWs) against them due to their non appearances in the matter. The case involves Khalistani outfits like Khalistan Liberation Force (KLF), Babbar Khalsa International (BKI), and International Sikh Youth Federation (ISYF), along with north India-based gangsters. They are suspected of being involved in terror attacks, arms and drug smuggling from Pakistan using drones, targeted assassinations, and extorting money from industrialists, businessmen, and professionals. /IANS