Really?  Do you not know how the law works?  The witness states he/she took pictures of the man and his car's license plate.  That does not equal conclusive evidence that he stole sand.  It would come down to one person's word against the other.  He could always claim the buckets were empty.  Unless the witness has uninterrupted video of the suspect clearly filling the buckets with sand, carrying them to and loading them into his vehicle, and driving away, then there is no conclusive evidence of wrongdoing.