According to the Sección de Estadísticas del Departamento de Planificación del Poder Judicial (Statistics Section of the Planning Department of the Judiciary) the number of murders presumed by hired killers in 2010, went from 13 victims in 2009 to 40 in 2010, placing the La Carpio, Leon XIII, Los Cuadros y Guararí de Heredia as the places of highest incidence. Judicial authorities presume that organized crime groups, use this method to assert their interests in various criminal activities, as they are listed in order of importance: drug trafficking, gang revenge, robbery of drug traffickers (known as tumbonazos) and executions tied to the sale of illegal drugs. However, statistics show a slight increase in intentional homicides during the past year, compared to 2009, from 525 to 527 victims. The study found that the rate of homicide victims per 100.000 inhabitants remained virtually unchanged from 2009, settling at 11.5%. The existence of homicides associated with what is known as "error or omission," or those who were not the target and suffered mistaken identity or omission by the murderer, almost doubled in 2010 over 2009, for a total of 16 deaths. Also, the number of foreigners killed in the country increased by 7.6%, bringing the figure to 112 individuals, Nicaraguan and followed by Colombian nationals being the target. The use of firearms to commit homicide, again saw increases during 2010, bringing the total number to 319, which is equal numbers in 2008 and the highest throughout history. Good news for women as statistics indicate that the number of femicides dropped in 2010, from 15 victims in 2009 to 10 last year. However, the major cause of femicides continues to be attacks by cohabitants (60%) and spouses (40%). Contract or hired killing (sicario in Spanish) is a form of murder, in which one party hires another party to kill a target individual or group of people. It involves an illegal agreement between two parties in which one party agrees to kill the target in exchange for consideration, monetary, or otherwise. The hiring party may be a single person, a group of people, a company, or any other kind of organization. The hired party may also be one person, such as a hitman, or a group of people, or an organization. In most countries, including Costa Rica, a contract to kill a person is void, meaning that it is not legally enforceable. Any contract to commit an indictable offense is not enforceable. Furthermore, both the actual killer and the person who paid the killer can be found guilty of murder. Contract killing provides the hiring party with the advantage of not having to be directly involved in the killing. This makes it more difficult to connect that party with the murder. Throughout history and in many different parts of the world, contract killing has been associated with organized crime and also vendettas. For example, in recent United States history, the gang Murder, Inc., which committed hundreds of murders in the 1920s to the 1940s on behalf of the National Crime Syndicate, is a well-known example of a contract killer.