A true informant is somebody on the inside, engaged in some sort of criminal activity or the knowledge of such, that for either selfish motives or for the greater good, feels a necessity to inform police authorities of this activity and after such communication will either continue in his former role as he was with the oversight of a particular police agency or will be essentially immediately utilized to turn State's evidence against the alleged perpetrators of the crime or crime in process. The other type of informant, which unfortunately is far more prevalent, is the fake informant, an informant created by circumstances and selfishness, that is either incapable of doing the time for a particular crime that he has been charged with, fearful of retribution by someone or something, and in return for a lesser sentence, or being let go, is given the assignment of infiltrating certain crime targets and reporting such to appropriate law enforcement agencies.
Informants are only valuable to law enforcement agencies if they have actionable activities to report, if they do not have these, any funding that they receive for expenses, for their cover, for their lifestyle, and for compensation for their "work", will be reduced or cut-off completely, to which they may have to return to jail or be relieved of their duties with little chance of employment opportunities that pay well. A significant portion of informants are selfish, desperate, and of less than a worthy character, which is a significant downfall of informants in the first place. I mean, if you take a lowlife liar and make him an informant, what sort of real actionable information will he provide you that isn't already compromised in some way, form, or manner?
Further to the cause as why informants are a contradiction in action, is their ability to help instigate and to plan criminal activities in the first place. From my viewpoint, an informant should never be permitted to engage in criminal activity as aiding and abetting a crime in progress, is a crime, no matter the cover, and so unless the informant is essentially passive in his actions, he is literally changing history by participating in it. In today's hi-tech world, the need of physical informants should be at a new low, as recording devices and the like have never been more prevalent and more effective than they are today. Police should be satisfied with a hands-off role in which they merely observe and record activities and then make a conscious decision on what to do base on their real-time observations and experience.
Law enforcement should be very particular about the informants that they work with and there should be a strict oversight committee monitoring the activities of such. There are always going to be people that will trade information for money, information for freedom, information for their beliefs, and those communication lines should therefore remain open and vibrant. What really isn't needed is the manufactured informant, in which law enforcement insists that they must have an informant to keep tabs on a certain non-desirable organization or people because they lack inside information about said target and then go out and actively seek an informant of dubious value and integrity. Doing so creates a very slippery slope, a slope that isn't good for America, isn't good for Americans, or its ideals, or its standards.
Remember that two wrongs don't make a right, it's far better to hold yourself responsible and accountable to that higher standard.