Larceny

What is the name of your state? michigan
6 months ago my brother found a dog on federal land obviously starving to death. he took the dog and cared for it until someone else claimed it was theirs. they went through the police to have the dog returned, the police threatened to get a warrant for larceny if the dog was not returned. he let the dog go with the officer. 3 weeks later he appeared in court on an unrelated charge of dui, and was told there was abench warrant out for him for larceny, for the dog. he was also told if he pled guilty to the dui then the larceny charges would be dropped. how can they blackmail, someone with unrelated charges?

I will guess he is about to receive a ticket for the dog being of leash and without license.

"he was also told if he pled guilty to the dui then the larceny charges would be dropped. how can they blackmail, someone with unrelated charges?"
*** This has nothing to do with 'blackmail'. It is common for a prosecutor to consolidate charges and agree to dismiss the lesser charge for an agreed plea on the stronger. Saves money for the taxpayers and defense costs for the suspect.