Hmmmmm.... Another Felony & Mayhem title on sale at $1.99 in the US. This is odd for them - I'm going to have to look later today and see if they have a sale going on or something...
Killer Instinct is the first in the Charlie Fox series by Zoë Sharp. I haven't read any titles in this series, but have had my eye on it for a while, so am happy to get a chance to try it out.
It's also a little bit odd, because there are Smashwords versions of Sharp's Charlie Fox titles too, including an omnibus of the first three titles for $7.99 (coupon/VIPable at Kobo), which might be a better deal if you want to read a chunk of the series. In any case, though, here's info on the $1.99 F&M version.
Kindle US:
https://www.amazon.com/dp/B016E9QDEW
Kindle US/Smile:
https://smile.amazon.com/dp/B016E9QDEW
Kobo US (coupon/VIPable):
https://www.kobo.com/us/en/ebook/killer-instinct-28