Usually, the bigger and more complex a potential criminal enterprise, the longer it can take to arrive at charges. I'm not all that au fait with the Romanian criminal system obviously, but in general it's not usual for people to remain uncharged for a considerable amount of time, given that prosecutors will always try for the most serious charge first. It's a lot harder to scale up a charge than it is to scale down.
Of course, it could equally be that they don't have enough to charge them, but then there would be no cause to continue having them incarcerated. I'd suggest they are taking their time to build a case against him, before issuing the charges. Wise, given his media celebrity and social media following.
Any investigation involving a high profile individual, with a large and volatile fan base, should be taken slowly, and charges only brought when there's a high degree of certainty over criminality.