IMHO, you need to be very careful not to study something that will get you in too much trouble if you use it. Many of the law enforcement officers I know who study train in Aikido because of its emphasis on control not strikes. Takes longer to get proficient, but is well suited for your job. The other recommendation would be FMA (Fillipino Martial Arts) of Kali, Escrima, or Arnis. The emphasis is on stick work at first which gets you used to going against weapons. Most of the counter attacks take aim at the attacking limbs first before going to the body. Some of my training mates who are also law enforcement officers say it allows them to stop there since hitting to the body and doing too much damage will get them in trouble. IMHO, Aikido and Kali balance each other well. There is a Police Martial Arts Association (PMAA) mailing list. Check with your department for what is approved. Hope this helps in some small way.
Lynn Tenshinkai Aikido/Lucaylucay Kali
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