A Matter of Justice is the eleventh book in Charles Todd's Ian Rutledge series. It's on sale in the US right now for $1.99.
Kindle US:
https://www.amazon.com/dp/B001NLKSZC
Kobo US:
https://www.kobo.com/us/en/ebook/a-matter-of-justice
The blurb is pretty much useless, just a bunch of generic praise, but here it is if you want it: