264. The SPT also recommends that the Paraguayan authorities ensure that the right to file a complaint or appeal with respect to torture and ill-treatment can be exercised in practice and that the principle of confidentiality is duly respected. Police staff must not interfere with the complaints procedure or screen complaints addressed to the competent authorities, and must not have access to the content of the complaints. The SPT recommends that rules should be drawn up for the handling of complaints by police officers, covering the forwarding of complaints to the competent authorities and the duty to provide the necessary materials for drafting a complaint. 265. The SPT recommends that a review of police salaries should be carried out to ensure that they are appropriate. The equipment required for police staff to do their job must be provided by the authorities. 266. The SPT recommends that police personnel and officials assigned to police stations and other detention centres should receive suitable training in guarding persons deprived of their liberty, including human rights training, and in the proper use of registers. 267. The SPT recommends that the Paraguayan authorities should establish a system for the effective monitoring and supervision of the work of the police by senior police officers . 268.The responsibility of police officers who commit acts of torture or inflict ill-treatment on detained persons, as well as the responsibility of senior officers who instigate, encourage, consent to or acquiesce in such acts, must be fully investigated both through internal police monitoring mechanisms and through competent prosecutorial and judicial authorities. 269. The SPT recommends that an audit of the police stations holding detainees should be conducted as soon as possible so as to ascertain what improvements can be made to the places of detention at existing facilities, at a modest cost: (a) The audit should be carried out by a multidisciplinary team drawn from the various sectors involved to date in visiting prisons; (b) Police stations should be given a budget to buy food for detainees, who should receive at least twice a day meals of sufficient nutritional value to maintain their health and strength; (c) Material conditions in the cells should be improved immediately, especially with regard to minimum floor space, cubic content of air, lighting and ventilation; (d) Persons deprived of their liberty should be given at least two litres of drinking water a day, systematically and free of charge; (e) Persons deprived of their liberty should be given regular access to toilet and shower facilities, and persons having to spend the night in detention should be given beds with mattresses. The cells should be cleaned regularly by police station staff. The sanitary installations should be sufficient to enable every prisoner to comply with the needs of nature when necessary and in a clean and decent manner. 270.The SPT recommends that, where possible, persons detained in police stations for more than 24 hours should be given the opportunity of having at least one hour of exercise daily, outside their cells. 271. The SPT recommends that, unless police staff have the necessary medical training to diagnose detainees ’ ailments, they should immediately authorize any request by a detainee to see a doctor. 272. The SPT recommends that female detainees should be transferred to police stations that have female officers to guard them and suitable facilities for ensuring they are separated from male detainees. 273. The SPT recommends that the State party should take the necessary steps to increase female police staff at police stations. 274. The SPT recommends that the State party should, as a matter of urgency, put an end to the practice of prolonged detention in National Police premises. The SPT recommends that persons being held in preventive detention while awaiting trial should be transferred immediately to prisons where they should be separated from convicted persons. To this end the State party should take the necessary interim measures to house the detainees in conditions compatible with human dignity. 275. Police officers should receive clear, categorical and periodic instructions on the absolute and mandatory prohibition of any form of torture and ill-treatment and such prohibition should be included in such general rules or instructions as are issued in regard to the duties and functions of police personnel . 276. In accordance with the obligations entered into by the State party under articles 12 and 16 of the Convention against Torture, a prompt and impartial investigation should be conducted wherever there is reasonable ground to believe that an act of torture or ill-treatment has been committed. Such an investigation shall take place even in the absence of a formal complaint. 277.All police stations and units in the country should have information available and visible to the public on the prohibition of torture and ill-treatment as well as on how and where to file complaints concerning such acts. 278. With a view to reducing impunity, police officers who do not wear uniforms when carrying out police duties (in “