Judgment B.P.Singh and B.P.Sharma JJ. 1. The petitioner has impugned the order of detention Annexure-1 dated 13th August, 1995 whereby the District Magistrate, Gopalganj has ordered for his detention under Section 12(2) of the Bihar Control of Crimes Act, 1981. 2. For the disposal of this writ petition, it is not necessary to notice all facts except those which are necessary for considering the submissions urged before us. Mr. Ashok Kumar, J. C. to AAG HI appears on behalf of the State and submits that he has filed a counter-affidavit and the same has not been included in the brief. We have obtained a copy of the counter- affidavit which is said to have been filed on behalf of the State. 3. The order of detention proceeds on the basis that the petitioner has a criminal background and the ground of detention refer to three recent cases in which the petitioner is involved. On the basis of those cases the District Magistrate was satisfied that it was necessary to detain the petitioner under the provisions of the Act with a view to preventing him from acting in a manner prejudicial to public order. 4. In paragraph 3 of the writ petition the petitioner has. clearly averred that the petitioner was languishing in Gopalganj jail since 10-4-1995 in connection with a criminal case against him. In paragraph 4(D) of the counter-affidavit it is stated that the petitioner was undoubtedly under custody on the day the said order was passed, but there was likelihood of his release on bail and that would have resulted in a panic in the area of his criminal activities. The counter-affidavit has been affirmed by Mr. Arun Kumar Singh who has been posted as Deputy Collector, Gopalganj. The counter-affidavit has not been affirmed by the detaining authority and therefore.it does not have much value so far as the question of satisfaction of the detaining authority is concerned. 5. Neither the order of detention nor the grounds of detention refer to the fact that the petitioner was already confined in the Gopalganj district jail when the order of detention was sought to be served upon him. Counsel for the petitioner therefore, rightly urged that the detaining authority did not have knowledge of the fact that the petitioner was already in custody and there was no necessity to pass an order of detention. 6. Counsel for the petitioner therefore, rightly urged that the detaining authority did not have knowledge of the fact that the petitioner was already in custody and there was no necessity to pass an order of detention. 6. It is by now well settled that the extraordinary power vested under Preventive Detention Laws has to be exercised only if it is absolutely necessary to do so having regard to public order. The power cannot be exercised by the detaining authority without considering all aspects of the matter which have a bearing upon the question of detention. Normally a person who is at large may be detained under the Preventive Detention Laws but decisions of the Supreme Court and the High Courts have established that even in the case an of a person who is confined in a jail in connection with any criminal case, order of detention may be passed. In such cases, however, the material must disclose that the detaining authority was aware of the fact the petitioner was in custody and yet he considered it necessary to pass an order of detention. The material must further dis- close that the detaining authority apprehending release of the petitioner in near future, considered it necessary to pass an order of detention as he was satisfied that on being released the petitioner may again indulge in antisocial activities and act in a manner prejudicial to public order. 7. In the instant case we find that the detaining authority was not even aware of the fact that the petitioner was already in custody. That being so, there was no question of applying his mind to the question as to whether despite his confinement in jail it was necessary to pass an order of detention. In these circumstances, we therefore, find that the satisfaction reached by him in ignorance of the crucial fact cannot be justified. The order of detention is, therefore, clearly illegal. 8. We, therefore, quash that order, Anncxure-1 dated 13-8-1995 and its confirmation by order dated 21-10-1995 issued on 10th November, 1995 and direct that the petitioner be released forthwith unless required in connection with any other case.