Name the Missing Item
Place several random items on a large baking sheet or tray. Examples include a costume jewelry diamond bracelet, an MP3 player, a large rhinestone or other faux gem, and a watch. Show the children the items for about a minute, then take the tray out of the room. Remove one item, then tell the children a robber came by and stole an item from the tray. The first player who can tell you what item is missing from the tray wins the game, and you can award him with his very own toy police badge.
Pass the Handcuffs
Have the children sit in a circle, and hand one player a pair of toy handcuffs. Play the theme song "Bad Boys, Bad Boys," and have them pass the handcuffs around the circle. When the music stops, the player holding the handcuffs "goes to jail" -- i.e., is out of the game. The last player remaining in the game wins the game and the pair of handcuffs.
Cops and Robbers Balloon Game
Use a rope to section off three spaces in an open field outside. One section is the "bank," one is the "robbers' hideout" and one is the "jail." Place a bowl of 10 water balloons in the bank. Divide the players into two groups, cops and robbers. The cops must try to protect the water balloons, and the robbers must try to take the water balloons to their hideout. If a police tags a robber, he must go to "jail" and cannot come out until another robber tags him. Set a timer for five minutes, and after five minutes count how many balloons are in the hideout. The cops and robbers then switch positions, and the robbers who have the most balloons in the hideout after five minutes win the game. If any water balloon breaks, it does not count.
Rook the Crook
Tell an adult to wear a costume jail outfit, available online and at Halloween costume shops. The children are all police and must arrest "Rook the Crook." Cut the back off a large appliance box, and cut a hole in the side of the box large enough for an adult's head. After the children drag Rook the Crook to "jail," have them stand about 10 ft. from the box and give them a bucket of water with sponges. The children take turns tossing the wet sponges at Rook the Crook when he peeks his head out of the hole. Award a few small prizes to each child who participates in the game.