UGH this breaks my heart. I would feel sorry for the person who ever even tried with me. I've had hundreds of people ask me to buy Tyson, or if I was going to breed him, etc. My reply is always this: "He is neutered, he has several health issues, and is on several medications, and has an implanted microchip with a locator attached.
Is any of that true? Only the neuter part The whole point is to make him undesirable, the people looking to steal usually want them to sell them or to breed them; the locator part is a scare tactic. I hope the person who took those dogs gets what's coming to him, and they are returned home safely.
And not to be rude at all - but I never leave Tyson unsupervised outside EVER. Never.