Methods and systems for intelligent signaling-router-based surveillance are disclosed. A surveillance and signaling router receives call signaling messages, identifies call signaling messages associated with users under surveillance and determines a surveillance type for the call signaling messages. If the surveillance type is content-related, the surveillance and signaling router forwards the message to a call server. The call server replaces parameters in the message and in subsequent messages so that the call is transparently set up through a media proxy server. The media proxy server copies the media stream to a delivery function. If the surveillance type is non-content-related, the surveillance and signaling router sends a copy of the message or information extracted from the message to an external device.