if you case is expunged then its as if you never had one, therefore its not on your record I presume.
This should help you.http://dps.mo.gov/dir/programs/post/licensing.asp
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Based upon the facts you've given, you are not a Felon.
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Although your main concern seems to be whether or not you would be eligible for Missouri P.O.S.T. certification, a bigger concern would be whether or not a particular department would hire you. Many academies may accept you, but you could have a hard time finding a job. That being said, for many departments your status with the military, the amount of time since the offense and honesty during recruitment will be helpful. I suggest you get an official copy of your California criminal record, Missouri criminal record a your military record. Take these with you and speak with a recruiter for some police academies and departments and see what they say.
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