The fifth series of the crime drama spin-off focusing on an elite group of New York cops continues. In this week’s season finale, Logan and Barek investigate the double homicide of a husband and wife, in which the main suspect is the couple’s teenage son.

After Dan and Lily Colemar are found murdered in their suburban home, the Nassau County cops are quick to point the finger at the couple’s troubled son, Kevin. A college dropout, he had recently moved back home due to money problems. Not only do his shoes match the prints found at the crime scene, but there is also no sign of forced entry to the Colemars’ house. The detectives learn that the night before, Kevin had borrowed Lily’s car to visit Marcus, an old highschool buddy. While questioning Marcus, the pair receive a call to say Lily’s car has been found in a ditch. Rushing to the scene, Logan checks the car’s satnav and finds that the device has recorded the vehicle’s last journey. “Some days you just get lucky,” he shrugs.

Logan and Barek waste no time in tracking Kevin down. It transpires that he is on the run from two drug dealers to whom he owes $6,000. Kevin is adamant that the dealers are responsible for the murders. But Dan had agreed to bail his son out and had even withdrawn cash from his bank account to do so. So where is the money now?

Meanwhile, local police arrest Kevin on suspicion of two counts of murder. Detective Carson Laird drops a bombshell in the interrogation room – Lily was still alive when police found her lying in a pool of blood. Before she died, she told them Kevin was the culprit. “You were high, Kevin. You lost your temper. You went to your room, you got a bat and you killed your dad and your mom.” With drug-hazed memories of the night, Kevin falters. “I must have,” he says, before signing a confession.

But a surprise development complicates matters for Logan and Barek. It turns out that Detective Laird runs a cabinetry business as a sideline to his policing duties. One of his clients is Wallace Kenter, a close personal friend to the Colemars and Dan Colemar’s partner in an art business. “I don’t know what they call it in Nassau County,” muses Logan, “but in the city we call it a conflict of interest.” Logan and Barek hotfoot it to Kenter’s gallery to question him. He claims to be a small-time art dealer who sells his paintings for a modest profit. But Barek spots holes in Kenter’s story, especially when the detectives learn that the art shops are being franchised, and that Dan had a 50 per cent share in the business. “He talks like an artist,” she observes, “but he’s got his eye on the bottom line.”

Could the meek and mild painter really have had his two best friends murdered simply to claim Dan’s cut of the business? Or should Logan and Barek turn their attention to another suspect – excon Jules Bremner, who has an incriminating injury that could link him to the murders?