It should be illegal for law enforcement not currently participating in a proper sting operation to lie to the person they wish to investigate. But it's not.
It is in some jurisdictions. In Illinois and Oregon, laws have been passed that prohibit law enforcement officers from using deception when dealing with suspects under the age of 18. Other states, such as Washington, Connecticut, Delaware, and New York, are considering similar legislation that may extend these prohibitions to all individuals being interrogated.
