answer:What kind of evidence would you have that he participated in the theft? He could have claimed that he purchased the mower from a private party – and who checks the serial numbers on every piece of used property that they buy? Perhaps with a lot more investigation and getting the thieves to participate in some kind of sting of the deputy, where he might admit to knowledge that he was receiving stolen property, you could have made an effective arrest. I doubt that the arrest you might have made simply knowing that he had the mower would have stood up in court. It would have wasted the prosecutor’s time, caused a scandal and bad feelings with the sheriff (for not letting him handle his own dirty laundry privately) – and the evidence would have been tied up for longer awaiting trial, and the charges would not have resulted in a conviction. This way the property is restored to its owner, the sheriff gets to handle his dirty deputy, and justice is done – even if there was no conviction.