Okay, I am going to assume that the paintings are worth LESS than $25,000.
There are two ways to go about handling this, and they can be done at the same time.
First, one can pursue this from a criminal point. This begins by filing a complaint which you already did. The police investigate and then pass the file on to the prosecutor who makes a decision whether to charge someone or not. This can take months and the decisions is not yours to charge or not, but the prosecutor's. This report should be filed ASAP and at the police station closest to you.
The other way is via civil suit, for conversion (civil theft). You would sue the company if they had their employees be the movers, as the company is liable for whatever wrongful acts the employees may do during their employment time via doctrine of respondeat superior.
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