The rapid growth of Science and Technology, in the twentieth century has developed the quality of life of people all over the word, but the same technological advancements can also be used by the terrorist groups who use these sophisticated technologies for destructive purposes and terrorism. In order to fight against terrorism, the law enforcement agencies and organizations have to apply their own special investigation methods or techniques and the advanced investigation tools and techniques.

Special Investigation Techniques are used by law enforcement agencies and officials for the investigation purposes to gather information of the suspected person or persons using a systematic approach without the knowledge of the suspected person(s).

Some of the Investigation Techniques used by the law enforcement agencies against terrorism are undercover operations, front store operations, observation, electronic and cross border surveillance, interception of telecommunications, searches and Informants.

From the information collected using these methods a typology of special investigation techniques is prepared for a better understanding of the investigation. Special investigation techniques are used by police forces to collect and process data and information related to the crime or offence such as evidences and identification of criminals. The information processing phase of the law enforcement agencies includes collecting data, recording, adapting, extracting and deletion, etc. All the information gathering activities must be regulated by law and it is subject the review of the law. All the actions taken by the law enforcement agencies which can impact on a person’s personal life and privacy must be regulated by law. The searches and the information of an individual must be authorized by law.

When there are threats by terrorists in various parts of the world, it is important to share information between one or more law enforcement agencies of various countries. The distribution of information between the security and law enforcement agencies, across countries, is very important which is necessary to prevent activities of terrorists and other criminals, all over the world.

In the process of Investigations of terrorism, the police force has to work with other intelligent agencies and military. This may be a complex and a risky process since   this may blur the difference in the rights and duties of the police and army which may result in militarization of the local police force and weakening the army forces. So there should be a clean definition about the function of the police force for the investigations on terrorists.

Several Regional and International organizations of human rights emphasize the risk of inequalities on terrorist investigations between the law enforcement agencies all over the world. So, various international agreements have made between countries for the successful detection and investigation of the activities of terrorists and proper prosecution of terrorism.