It depends on the department you want to work for I have been having the same problem I have a Bachelor's of Science in Criminal Justice w/ concentration in Forensic Investigations. I want to work for Kansas City, Ks police which is where I live and they require you to go through the Academy and be a patrol officer for three years BEFORE you can apply for a crime scene technician job. I am 42 and don't want to be an officer either I just want a entry level crime scene tech job. I will clean toilets at the jail just to get my foot in the door!
There are many agencies throughout the Unites States that hire civilian CSI. You do not need to be a police officer at those agencies. If you look at some of the employment listings on this site on the Employment Page you will see that only one of the hundreds of them require you to be a police officer.
There have been many discussions on this forum about this. Look in the Careers subcategory of the Forum to read some of the posts.
Vaneh Hartoonian wrote
i don't know if this has been asked but do you have to be a cop before hand to be apart of csi.
because i wanted to be a detective and an officer himself told me 5-6 years street on policeman work.