are tightly organised, the groupings are often held together by family ties, relationships and protection. At the centre is usually just one person who secures the loyalty of his or her followers through small benefits. Again and again, movements operating nationwide consist of networks of local groups. Information on membership numbers is very uncertain and fluctuates. A 2006 study puts the total number for the 15 to 20 large martial arts groups alone at 20,000, with an estimated further 90,000 unregistered members. This would mean that 70 % of young Timorese men practise martial arts. Conflicts between the groups are not only carried out with physical violence, but also with weapons. Industrially manufactured pistols and rifles are frowned upon due to an unwritten law of the gangs, so deadly violence does not escalate as much as in neighbouring Papua New Guinea. However, it is safe to assume that those groups that work as security or have police officers as members have access to real firearms. It is simple, homemade weapons, such as simple firearms (rakitans) that shoot nails, small metal arrows (rama ambons) and also real bullets, that are becoming more common. There are also stone and arrow slingshots, bows and arrows, knives, traditional swords (suriks) or simply stones. The arrows are prepared with poison or battery acid. They are usually shot at a relatively long distance in a high arc and can therefore be found all over Dili in tree tops or telephone poles. Simple explosive devices, such as Molotov cocktails, are still rare. In connection with gangs, there were at least 100 fatalities in 2007. Protection rackets are a major source of income for most groups and have become a threat to business and investment. This affects small stalls as well as large construction companies and supermarkets. Some shops and companies have unofficially signed contracts for "levies" or "donations" with groups to get protection from attacks and extortion, which is now widely accepted. In some cases, professional security services have emerged from the groupings. Mostly, however, these are payments extorted by small, local groups. However, these small groups may well cooperate with larger organisations, such as crime organisations from Indonesia or the People's Republic of China. During the 2006 unrest, some groups offered themselves as mediators in the conflict for a fee, after they themselves had caused the problems. Some groups work for corrupt politicians, landowners or crime