These two books have a few things in common. They've got "devil" in the title, obviously. They have both been translated from other languages, and both feature a lead detective who is an alcoholic. "The Devil's Star" is from Norwegian author Jo Nesbo and is actually the third book in a series featuring detective Harry Hole, but it was the first one to be translated into English. Therefore, much of this book makes reference to events from a previous novel in which Hole's police partner was murdered, and he suspected co-worker Tom Waaler of the crime. In "The Devil's Star", Hole is forced to get over his alcoholism and learn to work with Waaler, since they have both been pared up to investigate a rash of murders in which the victims have been found with a diamond pentagram on their bodies, and one of their fingers removed. It's a fairly standard mystery, and I wasn't all that interested in the subplot about whether or not Waaler was a dirty cop, but it kept me reading. I don't know if I liked it enough to track down the other books in the series, which have subsequently been translated and released (out of order), but you never know. Maybe I'll check the library.
"Devil's Peak" is from South African writer Deon Meyer. I'm actually only half-way through this one, and it's been very difficult to get into. The plot has alcoholic inspector Benny Griessel having to get over his alcoholism or risk losing both his job and his family. There have been a number of murders committed by a killer nicknamed "Artemis", and he is only targeting people who have abused or killed children. He's on this rampage because his own child was gunned down in a drive-by and the killers are still on the lam. There's also a subplot in which a prostitute tells a minister about her life, but as yet this element has not revealed its relevancy. I'm hoping it will all weave together into something interesting and surprising, but the pacing so far is not what you'd call zippy.
Having an alcoholic cop/private investigator as your book's hero/anti-hero really is becoming an over-used cliche. Lawrence Block has had the alcoholism-as-personal-demon thing covered since the 80s with his character Matt Scudder. There have been plenty of other novels with this sort of character, but they're not coming to mind right now. A similar cliche is found with female detectives/investigators in that they all seem to love cooking and going for a run. Inspired, obviously, by Patricia Cornwell's Kay Scarpetta character. I know that, being a popular genre, crime novels are inevitably going to have their own list of cliches, but would it really be that bad if your main cop/investigator came home at the end of the day, enjoyed a couple of beers, watched TV and fell asleep at 8.30?