It is difficult even for a native speaker (like me) to understand this kind of text. Besides, it is like a “patch” to some previous rules, so maybe one needs to read the whole in order to understand it correctly.
But as far as I can understand, it says that in order to uncover or prevent crime, police can use hidden mikes and cameras, can take pictures or audio/video records, or can put under surveillance suspected people. In order to do this they need a permission from their supervisors. The rules about when this surveillance is allowed are decided by the Committee for Preventing and Fighting Organized Crime.
This committee is headed by the Minister of Interior, and includes the Minister of Justice, Minister of Finance and Economy, General Prosecutor, the head of SPAK (Special Prosecution Against Corruption and Organized Crime), the head of Intelligence Service, a couple of policy directors for the sectors of fighting against terrorism, against money laundering, etc.
The surveillance for a certain subject cannot last for more than 3 months. In special cases, with permission from the committee, it can be extended for 3 more months.