Law enforcement agents rarely catch an experienced perpetrator red-handed. Instead, they usually will need to monitor a suspect's activities for weeks or months to prove the commission of a crime. Basic surveillance techniques are instrumental in criminal investigations. The FBI has an entire army of operatives who specialise in this area. Police academy or private security training usually provides a quick introduction to surveillance techniques but no officer will make detective without significant field experience.
Tailing a suspect will require a lot of work behind the wheel. You need to find out who he meets and sits with and, possibly, who his friends meet and sit with. In the latter case, you will work on a team of surveillance operatives. They usually fan out to provide maximum coverage of the target. One common technique is a revolving tail, where different vehicles follow the suspect at different times so he does not recognise them. Another common technique called "leapfrogging" involves overtaking the target's vehicle then falling back. With the introduction of GPS systems, vehicle tracking has become easier, though traditional methods still are employed in many cases.
Also known as "shadowing," foot surveillance involves physical observation of the target without the use of a vehicle. In large metropolitan areas such as New York City, suspects may not want or need to drive. This can make surveillance much harder to conduct. Following someone through a crowded train station offers many more routes of escape than two cars on a highway. The famous subway scene in the true-crime thriller "The French Connection" is an excellent case in point of how an experienced criminal can elude a police dragnet through fast footwork.
Smart crooks know better than to talk about illegal activities at home or in their cars. Usually. Phone taps and listening devices often produce many hours of irrelevant material but a single utterance might be the last puzzle piece for an indictment. Electronic surveillance involves technical expertise as well as the street smarts to install devices without detection. However, it also entails a good grasp of the law. Wiretapping a phone or monitoring an e-mail account is only admissible in court with the approval of a judge. An office must supply adequate evidence that a crime has been or will be committed.
Surveillance cameras can be found everywhere from a military installation to your local convenience store. In many cases, taped footage may be useful in a criminal investigation such as a bank robbery. Forensic video experts provide valuable information in how a crime was committed. Additionally, law enforcement may use video to monitor suspects. For instance, if a criminal is wary of physical tails, a long-range camera may be employed to monitor his activities. Shotgun mics may also be used to obtain a soundtrack from distances as far as several hundred feet away.