Free for now at Amazon (US, at least)
Donato & Daughter : originally published under pen name Jack Early, current version shown as Sandra Scoppettone
http://www.amazon.com/Donato-Daughte.../dp/B004SJF586
The setup: Dina Donato is the head of an elite police squad tasked with stopping a serial killer. Her estranged father is an old-school police officer, currently in department bad graces for a botched investigation. Dina chooses to partner with her father to work on the case, because she feels he's the right man for the job. The action is good, and there's good character development and interaction. Father vs. daugher, new-school vs. old-school, cops vs. killer. Good writing all around.
This seems to be part of Scoppottone's release of some back catalog material. I checked it out from the library years ago, and enjoyed it enough to keep my eyes open for a used copy (since snagged). The Jack Early pen-named series is enjoyable medium weight mystery reading, and I'd compare it in quality to some of the recent promo offerings from Poison Pen Press.
A scan shows that several of her other "Jack Early" ebooks are available at $0.99-$1.99. I'll be checking my memory and my bookcases, and will be picking some up. Scoppettone apparently was nominated for an Edgar award, and won a Shamus award for some of these.
Not free, probably good picks (a couple or $2 books can be scouted from her author page):
http://www.amazon.com/Creative-Kind-.../dp/B004M8T1C4 at $1
http://www.amazon.com/Razzamatazz-ebook/dp/B004OYTGJY at $1
KentE