Information translated from the Guardia Civil website regarding “denuncias”:
What is a denuncia?
A denuncia can be translated as a “complaint’s report”. 
A denuncia is a statement that a citizen makes to a law enforcement officer to make known to the authorities an act (or omission of it) which the citizen presumes is contrary to Law.
If you know the author or any witnesses of the illegal conduct you should provide the details needed for identification.
When can I report?
You can report whenever you can consider yourself a victim or a witness of an illicit act . In the case of minors or incapacitated persons, the parents or the Attorney General (Ministerio Fiscal) may file the denuncia.
What kind of denuncias are there?
There are basically two kinds:
Denuncia penal (criminal complaint): All those complaints that communicates the commission of a felony or misdemeanor contained on the law. In many cases, if there is not is a criminal complaint by the victim certain crimes and most misdemeanors cannot be investigated.
Denuncia administrativa (administrative complaints): Those complaints that reports an act contrary to administrative law (regarding PublicAdministrations).
How do I report?
You can report by any of the following ways:
In writing, by submitting a letter, which must be signed. The authority or officer who receives it will sign and stamp all the leaves in front of the person who delivers it.
Verbally, to a law enforcement officer who will collect your allegations in writing. Then both (the officer and the citizen) will sign the report.
In both cases the authority or officer receiving a complaint will note down the National Identity Card or any other document certifying the identity of the person who is filing the complaint.
If the person filing the complaint requests a receipt, it will be given.
To whom can I report?
To authorities, officers and agents who are responsible for investigating and punishing the allegedly illegal act.
Criminal complaints must be filed in courts, police officers of the place where the crime was committed or police officers of the residence of the complainant.
Administrative complaints must be filed with the territorial or institutional government officials. However, you can also report to any Security Forces (Guardia Civil, National Police, Autonomic Police or Local Police) with jurisdiction where the offence was committed or those of the place of residence of the complainant.
In the latter case, if during investigation of the complaint it is noted that the facts would constitute a criminal offence, rather than an administrative one, the complaint will be forwarded to the Judicial Authority.
If the offence is an administrative one, the denuncia will be forwarded to the competent administrative authority, may it be of the State, of any Autonomous Community, of any Municipality or Institutional.
What does a denuncia involve?
By filing a criminal complaint it begins a criminal court proceeding if the act depicted in it constitutes an alleged crime or offence against any Law.
The administrative complaint may result in:
Opening confidential reports to verify the allegations and identify the perpetrators.
Beginning of an administrative procedure for withdrawal of an authorization.
Prosecution.
A person making an administrative complaint must be given a receipt filed by the competent public authority This authority should tell you in due course whether there are grounds to open an administrative procedure or not. If it finally opens it, the same authority should communicate the outcome of it.
What are the consequences of false reports?
Article 456 of Penal Code states imprisonment or fines for those with knowledge of its false nature claiming to be victims of a crime or falsely accusing others as perpetrators of criminal offences.
The person who has been falsely reported may, in turn, report or even sue (querella) against whoever filed the false complaint due to libel and slander.
Information about Guardia Civil of Puerto de Mazarrón:
Our Guardia Civil offices are located in Puerto de Mazarrón, Plaza del Mar, nº 12.
Phone: 968 594 103
Snapshot in google maps: http://goo.gl/maps/tTBl.
The Guardia Civil officers are not entitled to know English, although some of them do. The final report should be in Spanish.
It is advisable to know Spanish or to be accompanied by someone who does in order to be assured everything was done correctly and/or written down in the final report.
Should you require further advice do not hesitate to contact the CRA:
Phone: 634 364 739 or email info@cracamposol.com