When an agency is working with a new provider, whats the best way to test to find out if there involved with law enforcement?
1. Conduct and arrange there first client

2. Ask are they affiliated with law enforcement

3. check them for mics or other trappings

Just DO NOT TALK TO THE POLICE.  Do not answer any questions.  If they won't let you go, ask them if you're being detained.  If they say yes, ask them why?  Ask them if you are being arrested, and if so under what charges.  Ask if you are being interrogated.  If they say you're being arrested, refuse to answer any questions without first consulting an attorney, and make sure they fully understand this.  You may safely state your name, address, social security number, and you should state that you're invoking your 5th Amendment rights.  The police do not have to read you your Miranda Rights until they begin the interrogation process.  Questions asked beforehand during the "Interview" will still be used against you in court, even if they do not read you your rights first.  Also, and even just as importantly, thing you say without it being recorded and or videotaped can be used in your own defense in court.  It will be considered hearsay.  

Remember, they have to prove your guilt.  You have no requirement to prove your innocence and you should never try because under the law you are presumed innocent until proven guilty.  They will use your anger, confusion, fear and uncertainty during interrogation to get you to say anything that can be used as evidence against you.  Interrogation can begin at any time, but they do have to read you your rights prior to interrogation.  If you have gotten to the point of being interrogated you MUST state your right to speak to an attorney before answering ANY questions, period.  You shouldn't have said anything prior anyways since you have invoked your 5th Amendment rights.  

Remember, the mantra "Nobody talks, everybody walks" works more often than not.

this is real important to remember

ANY THING  you say AT ANY TIME to a law enforcement officer ------can and WILL  be used against you.

and

NOTHING you say can or will be used to help you as stated above it will be counted as hearsay.

there is a youtube titled "why I don't talk to the police" check it out and study. You will be doing yourself a big favor.