In People v. Dreyden, 15 NY3d 100, 931 N.E.2d 526, 905 N.Y.S.2d 542 (2010), the accusatory instrument contained the arresting officer's statement that the defendant possessed a gravity knife. The Court of Appeals deemed that conclusory, saying that it "failed to give any support or explanation whatsoever for the officer's belief,"(id. at 103). In Dreyden, the court found that the failure to give factual support or explanation for the officer's belief was a "violation of the reasonable cause' requirement and amounted to a jurisdictional defect" (id.) The Court applied the test for a jurisdictional defect that was set forth in People v. Kalin, 12 NY3d 225, 906 N.E.2d 381, 878 N.Y.S.2d 653 (2009), to a case alleging the possession of a gravity knife pursuant to P.L. 265.01. The misdemeanor complaint in Dreyden failed to "give any support or explanation whatsoever for the officer's belief" that the defendant possessed a gravity knife. (Dreyden, 15 N.Y.3d 100 at 103.) A conclusory statement that an object recovered from a defendant is a gravity knife does not alone meet the reasonable cause requirement. An arresting officer should, at the very least, explain briefly, with reference to his training and experience, how he or she formed the belief that the object observed in defendant's possession was a gravity knife, as opposed to a pocket knife, craft knife or other type of knife that does not fit the definition of a per se weapon as defined in Penal Law article 265. (Dreyden, 15 N.Y.3d 100 at 104.) The Court of Appeals found that allegations of an officer's training and experience in the identification of gravity knives were necessary before a complaint alleging possession of a gravity knife in violation of Penal Law 265.01 would be deemed sufficient. (15 NY3d at 104.) However, the decision in Dreyden was based upon a finding that "a conclusory statement that an object recovered from a defendant is a gravity knife does not alone meet the reasonable cause requirement" of CPL 100.40 (4) (b). (15 NY3d at 104.)