What's a shonokin? Is it something non-canonical that you've homebrewed?
More or less. They're loosely based on the works of a local pulp author and Lovecraft successor named Manly Wade Wellman. The Shonokin are a race of near-immortals who were here before the American Indians (who they call Invaders) arrived. Due to lacking any surviving females, a war with the Invaders (which was really pretty damn awesome and rivals Bob's description of the Fomor War), and gradual attrition over the millennia, they've been reduced to less than a hundred individuals in loose cells around the country. They have a random grab-bag of powers including a poor man's shapeshifting (doesn't hide a couple key tells) and sponsored magic of their own. The mutants are a byproduct of their experiments in creating more Shonokin to restore their species, put to use as shock troops. They look like a hulking, misshapen human covered in large cancerous growths, and fight with fists or claws plus superhuman strength and resilience. There's more where the cop came from, but they mostly have been kidnapping homeless bums for that purpose, the cop was just someone they needed out of the way to insert an agent into a situation.
Current complications: one of my players has been instructed by the King of Autumn to kill all of the Shonokin in the city before the end of All Hallow's (in about a week, and I swear I started this plot before CD in October), or she will die. There's also a looming threat of the rage-eating local White Court sparking a riot of deranged berserkers if they don't get one of their own back (the Shonokin have her).
So I was thinking that a week is good time to figure out via dental records or identifying tattoos that this misshapen pile of extra crispy tumors is actually the rookie cop who went missing a few days back. Which means that the PCs may be able to make bail in the immediate future after sufficient justification as self-defense. The police will continue their investigation, and the fact that there's every chance the decedent was a cop will come to light at the worst possible time: Halloween Night. The PCs will either get arrested or go on the lam, just as the clock is ticking to zero for our poor autumn knight. And the riot will probably start around that time too.
For getting them out of jail or getting the cops off their back, there are dark powers willing to help, of course. The dark powers are always willing to help.