The Dutch police have repeatedly expressed the intention to further enhance cooperation with private and societal partners. At the same time, these private and societal actors have shown increasing abilities to take on police duties, due to new technologies, among other things. Through analysis of four collaborations from Dutch police practice and a systematic literature review, we formulate guiding principles for further development of public-private partnership (PPPs) to support the police function, while respecting the principles of the rule of law.