Secret police definition [1]
> Secret police (or political police) are police, intelligence, or security agencies that engage in covert operations against a government's political, ideological, or social opponents and dissidents. Secret police organizations are characteristic of authoritarian and totalitarian regimes.
Security police definition [2]
> In some countries, security police is the name given to the secret security and intelligence services charged with protecting the state at the highest level, including responsibilities such as personal protection of the head of state, counter-espionage, and anti-terrorism.
Specific example for Swedish 'Security Police'.[3] if you look up any EU agency with similar roles it will be found that they are all security, not secret.
1: https://en.wikipedia.org/wiki/Secret_police