The National Investigation Agency, NIA on Thursday arrested three people in Kishtwar, in Jammu and Kashmir in connection with the Delhi high court blast case. The arrested persons include the owner of a cyber cafe from where a Pakistan based terror group, Harkat-ul-Jihad-al-Islami, ‘HuJI' e- mail claiming responsibility of the blast had been sent.The NIA has announced a reward of five lakh rupees for any information from the general public about the blast culprits.Home Secretary RK Singh on Thursday said in New Delhi that shrapnel was used in the blast to maximise the impact and casualties.On Wednesday, officials had claimed that shrapnel was not used in the blast as it was carried out using pentaerythritol tetranitrate (PETN), which is a plastic explosive. Mr. Singh has also received the preliminary forensic report on the blast.The NIA and the Delhi police have ruled out the angle of the Santro car being used in the incident. Home secretary RK Singh said that the car had nothing to do with the incident. The car was merely a subject of dispute between two people.Meanwhile, another mail has been received by media houses in Mumbai and Delhi purportedly written by Indian Mujahideen who claimed responsibility for the Delhi High Court blasts. The mail claimed that another blast will take place at a shopping mall.Sources said as of now nothing was being left to chance and the origin of the mail was being ascertained and, if need be, the service provider would also be contacted.Talking to reporters in New Delhi secretary internal security U.K.Bansal said ,the agencies are seriously examining the purported IM