Security Clearance

I have a question that's directed to anyone that can be of help. I'm active duty military and am looking to transition to JSO once I am released from active duty. In order to know what kind of timeline I will be working with I was wondering, if I have a current valid Security Clearance will a new BI still be necessary? I know this usually takes a few months and I want to be able to plan my transition accordingly and as streamlined as possible. Thanks in advance to anyone that can be of assistance.

a background investigation is required for all new applicants... the security clearance just means you were clear when that check was done... what have you done since then... you will also have to do the polygraph and psychological eval as well in adition to the physical agility test, department health screening, and oral review board, in all your hiring process is about 5-9 months without any snags, with snags it can be over a year