This is not their responsibility. They are specialised agents that work on organised crime. They can only complement the work done by the police. The 2 words are not synonomous. Arrest refers to incarceration for not more 48 hours before appearing before a magistrate.
Prosecution requires evidence beyond a reasonable doubt.
If there is no evidence then suspects cannot be kept imprisoned. If this is done it would amount to unlawful arrest and detention. The key issue is investigation and swift prosecution. Conviction will act as a deterrent. They are trying to expedite the integration process.