from my understanding criminality is criminal - ie: has this applicant had any criminal behaviour in their past? have they served jail time, been convicted of a crime? - that is what we send the police reports for. Security i think means more like national security issues - ie: has this person been associated with known terrorists or terrorist groups? are they on a watch/no fly list for something? It is common for these things to be investigated by different agencies. For example, in the us, criminality may be assessed and reported by local/state police or the FBI. Security may not be, and that comes from whatever agency handles national security matters: ie: CIA, Department of Justice, NSA, terrorist watch lists, etc (although i am doubtful CIC is able to get reports from the CIA - unless it is an extreme case). The FBI report isn't going to show whether someone has been investigated for national security issues, from what i understand, so that is why further checks are necessary on CIC's end. Also, i'm sure there is some internal checks as it relates to the applicant's record/dealings in canada...
Thank you