Book Log 2020 #47: The Siberian Dilemma by Martin Cruz Smith

Russian police detective Arkady Renko is worried about his semi-official girlfriend, journalist Tatiana Petrovna, who does not get off the train that was supposed to bring her back from a month in Siberia, where she was investigating an oligarch with plans to run for president. There's enough danger in the story - crossing an oligarch has consequences - that Renko wants to go and find her.

Luckily (?) for him, an official reason crops up for him to make the trip. Renko's superior sends him to Siberia to check on the oligarch himself, a case motivated more by politics than the law. He also has to interrogate a Chechen prisoner, with an eye towards making sure the questioning leads to the prisoner's conviction. 

Renko handles these cases, and the search for Tatiana, with his usual mix of humor, fatalism, and skill at working the system. It's been interesting to see Renko adapt his experiences as a cop in the Soviet Union to the reality of Putin's Russia, which seems much more dangerous.