Harry Bosch novels: volume five: The Overlook; Nine dragons; The Drop. Michael Connelly. 2012.

The Overlook.

When a physicist is murdered in LA it seems the killer has no fear of publicity, leaving the body on the Mulholland overlook, a site with a stunning view over the city.

But this is no random killing. Before he died, the victim turned over a quantity of a lethal chemical to his killer - and Detective Harry Bosch knows he has more than just a single death to worry about. Suddenly Harry finds himself plunged into an investigation with a whole new and horrifying dimension……

Nine dragons.

Harry didn’t know the old man’s name. He and the murdered liquor-store owner had never exchanged a word. But twelve years earlier, a cop caught up in a deadly riot, Bosch had sought refuge in Mr Li’smstore and a bond of sorts had been forged.

Now it is his duty to find the killer. In his last desperate seconds of life, Mr Li had left a clue to his assailant’s identity. A clue that leads Harry into another world - the parallel criminal underworld of the Triads.

But unknown to Harry, the Triads have already entered his life, and repaying the debt could mean destroying the only thing he really cares about.

The Drop.

In then Open-Unsolved Unit, where Harry is investigating cases going back fifty years, what you pray for is a cold hit - when new technology matches old DNA evidence to someone who thought they’d gotten away with murder. But when a lab result links the brutal rape-murder of a teenage girl in 1989 to a convicted rapist who was only eight years old at the time of the attack, Harry needs to solve the mystery fast before the validity of DNA evidence in dozens of cases is challenged.

Then a city councilman’s son is found dead - fallen or pushed from a hotel window - and he insists on Bosch taking the case despite the two men’s fraught history. As the cases  circle round each other like complex strands of DNA, Harry begins to uncover two of the city’s deepest secrets………