Not sure which phone number to use to contact the police in Spain, I found this article on 'Tenerife Forum' very useful.
Often visitors simply don't know which one to call, and for a range of reasons, end up thinking the police aren't interested when they've simply called the wrong lot. If there's a communication problem, too, or it's an out and out emergency, then it's even more important to get it right first time. Here's a brief list of what the different forces cover, and how to contact them.
The Guardia Civil wear green uniforms and are considered by many to be the most respected and trusted police force in the country. They can be phoned on 062, and have wide-ranging responsibilities for national law-enforcement. Specifically, the Guardia Civil polices customs, ports and airports and is responsible for drug-trafficking and contraband investigation. They also have a bomb squad, deal with counter-terrorism, crowd control, security in rural areas with a low population and running the prisons. They are also responsible for highway law-enforcement.
The Policía Nacional wear a blue military style uniform, and are the main police authority responsible for handling criminal, judicial, terrorism and immigration matters, but their duties also include guarding public buildings and government figures. This is the force that officially deals with burglaries and muggings. They also deal with issuing you with a NIE, a Certificado de Registro if you are a foreign resident, or a passport and DNI if you are Spanish. To contact them, dial 091.
Policía Local wear blue and white uniforms, and deal with minor crimes such as traffic control, civil disturbances, drunkenness, and the enforcement of municipal laws, e.g. removal of business signs on pavements. They often impose on the spot fines, and are well known for conducting teams of grúas to tow away illegally parked cars.
This is a new force, with pink edged black uniforms, and is responsible for certain specialized tasks, including providing information, dog wardening, environmental and rescue missions, protection of minors and immigrants, crime prevention, large-event policing, and ensuring the strict observance of tourism legislation.