Avi deduces that Paul Serra murdered his wife after losing a significant amount of money in a crypto investment. Paul strangled Elisabeth and hid her body in cement at a construction site where he was installing underfloor heating.
John is found with a gun underneath him, and the word "Father" (written as "Av" in Hebrew or "father" in English depending on the translation/viewer interpretation) is engraved in blood on his forehead.
The investigation into Elisabeth Serra’s disappearance concludes with a violent confrontation and a grim revelation:
Captain Kathleen is placed on administrative leave following the shooting, her first time using her weapon in the line of duty. The Cliffhanger Ending
During interrogation, Paul turns violent, neutralizes Detective Earl Malzone, and attempts to escape. Just as Paul is about to shoot Avi, Captain Kathleen Davies fires her weapon, killing Paul and saving Avi’s life.