Hey there,

If you have completed graduation degree from a recognized University, then you are eligible for SI, ASI, IPS ooficer in Police. Your age should be in between 21 to 30 years. 

Engineer's part in police department could be the design and implementation of various gadgets used by the police or and domestic force…..These range from Stun Guns, Pepper Spray, Multi-terrain vehicle to Spikes, Jammers, EMP guns.

You can also impliment the Internet of Things(IOT) for developing various gadgets.

Hope this will help.