FBI Counterterrorism Division. "The Radicalization Process: From Conversion to Jihad". Federal Bureau of Investigation, 2006.

FBI Counterterrorism Division. "The Radicalization Process: From Conversion to Jihad". Federal Bureau of Investigation, 2006.

• Radicalization takes place through four distinct stages: pre-radicalization, identification, indoctrination, and action. This process is linear, but there is no reason that a individual at one stage will necessarily progress to the next stage (3).
• Pre-radicalization are the events and changes occurring in someone's life prior to radicalization that leave them vulnerable to being radicalized. Four general archetypes are particularly likely to become jihadists: jilter believers, those who seek acceptance through faith groups, those who convert as a form of protest, and those who reinterpret their faith along heterodox lines (3). 
• Radicalization can occur due to intrinsic, often through anger at the fault of current religious practices or their own sinful lives, or extrinsic motivations, like the need for social support and acceptance (5-6).
• During identification, individual start to become isolated from other friends and relationships outside of jihadist circles, committing themselves to Islam and only affiliating with other radicalized individuals (3, 7).
• The process from identification to indoctrination can occur in a number of different ways, depending on where the radicalized community exists and communicates. Radicalization almost always results, however, from foreign travel to meet radical groups (7-8).
• Individuals in this phase can sometimes be identified by increased isolation from their previous social life, frequent and new attendance of a mosque or prayer group, travel to Muslim countries, and outward signs of Islamic devotion, like growing a beard or wearing traditional garb (10).
• Indoctrination is the stage at which the individual is convinced that their beliefs require some form of action, but are unsure about what course of action to take. This is the stage when individuals are most vulnerable to active recruitment by terrorist organizations (3, 8).
• Individuals at the indoctrination stage can be identified by increased activity in Muslim groups, proselytizing their faith to others, conducting surveillance activities of sites, or attending training camps run by terrorist organizations (10).
• Action is the stage at which an terrorism-related offense is actually committed. This can mean violent attack, but also include involvement in recruitment, financing, and facilitating jihad (3, 8).
• All terrorist activity consists of three stages: preparation, planning, and execution. Generally US jihadists do not appear to be involved in preparing for or planning attacks against the United States (8).
• Action can be detected by travel without an obvious source of funds, suspicious purchases, especially of weapons or the ingredients for bombs, large transfers of funds to or from overseas accounts, or the formation of cells with other known jihadists (10).
• Radicalization can occur anywhere, but is especially common at universities, prisons, mosques, places of employment (3), or, increasingly, internet forums (7). Recruitment and radicalization most often occurs through a personal friend whose is themselves radicalized or part of a radical group (6).
• While financing of a terrorist organization is an important element of jihadism and the activists of radicalized persons, these organizations can also be funded accidentally through shady charities and other NGOs. It is important to distinguish between intentional and unintentional financing (9).