Bone to Pick

Too valuable to kill? Oh, but that was then.
XK9 Rex was bio-engineered and cyber-enhanced to be the most perfect law enforcement canine ever created. Transmondian spymaster Col. Wisniewski thought he could turn him into the most perfect weapon.
But Rex had other plans. Wisneiwski couldn't bend him to his will. The Colonel would have killed any other dog, but Rex was too valuable. Instead, Rana Station paid a literal fortune to add him and his XK9 Pack to the Orangeboro Police Department.
Now Rex and his Pack are working detectives on the trail of a criminal gang that blows up spaceships - and Rana Station has recognized XK9s as uplifted sapient beings. That means it's illegal to buy them, so they've stopped paying that literal fortune. And this gives Col. Wisniewski a new license to kill.
How far must Rex go, to dodge his old enemy's deadly intent and also crack the case?