tip lines?

[shinsplints]

Suppose I live in a major U.S. city and I know of a guy who has committed a crime and routinely carries drugs on his person. If I don't know where he lives, but I do know where he will be--for example, if he uses public transportation and will be at a certain bus or train stop at a certain time, can I call into a police tip line and have them appear in time to search him? I'm unsure of the consitutionality of that arrangement. If I were to call the cops and say, for example "a guy matching X description will be at this place at this time and will have drugs on him," will the cops go so far as to search that guy? If they do, is it legal and/or constitutional?

[Piggy]

That's going to be a tough one. Major cities tend to be busy and probably would not take that call as seriously as if you personally contacted an Investigator. In that case, you could establish a relationship with someone. Explain that you want to be left out of it, but you are willing to notify he/she when the situation is happening. That way the Investigator is more willing to take your call seriously as opposed to anyone else who may just be looking to set someone up for no apparent reason.