Lazarus season 1 ending explained: Who is the true killer?

Based on Harlan Coben's works, Lazarus Season 1 follows psychiatrist Joel Lazarus as he investigates his father Jonathan's mysterious and violent past. The season ends shockingly, revealing Jonathan's death and an even darker twist. Jonathan Lazarus, a serial killer with a history, is the true killer in Lazarus season 1.

Disclaimer: The following article contains spoilers from Lazarus Season 1. Reader’s discretion is required.

By the end of the season, the audience learns that Jonathan committed multiple murders over the years, manipulating those around him, including his patients, to cover his tracks. The series wraps up with a suspenseful cliffhanger involving Joel’s son, Aidan, which hints that the cycle of violence may continue, leaving the door wide open for a potential second season.

How did Joel discover Jonathan was the Killer

Joel discovers his father's dark secret in Lazarus season 1's finale. Joel suspects a serial killer killed several of his father's friends throughout the season. Joel discovers that Jonathan Lazarus was the killer, which is shocking.

Joel investigates after his sister Sutton's death and Jonathan's suicide. Joel begins receiving visits from the "ghosts" of his father's former patients, twisting the investigation. Jonathan allegedly killed Cassandra, Harry, and Imogen, whose ghosts appear. Joel discovers lies and manipulations linked to his father during his investigation.

Later, he comes to know the truth by listening to Jonathan's office tapes and talking to Alison, a detective involved in the investigations. Jonathan had been a serial killer for years, killing Cassandra, Harry, Imogen, and others. Jonathan murdered them and framed his patients and acquaintances to cover up his crimes.

What was Jonathan's motivation for murder

Jonathan Lazarus's beliefs drove his murders. He believed he was "helping" his patients by ending their suffering as a psychiatrist. He saw this as twisted mercy. He decided to “free” Cassandra and Harry by killing them because they were beyond saving.

Cassandra killed her boyfriend, Neil, in front of Jonathan, his first major murder. Jonathan helped her dispose of the body instead of reporting her. Jonathan also killed Cassandra after realizing she might reveal his involvement. Jonathan killed Harry, a troubled, emotionally unstable, sexually assaulted man, believing him irreparably broken.

As a respected psychiatrist, Jonathan used his position to manipulate the system to frame others for his murders, complicating his motivations. Detective Alison unknowingly helped Jonathan cover up by believing the suspects he mentioned were the killers. Jonathan falsely accused serial killer Arlo of murdering Imogen, despite knowing he was innocent.

Who is Aidan and why does the character matter in the ending

In the final moments of Lazarus season 1, Joel's son Aidan follows in his grandfather's footsteps, the biggest twist. Aidan is a mystery throughout the season, and his connection to Joel is revealed later. Joel's discovery of Aidan at Margot's murder scene reveals his true significance. Margot, Jonathan's personal assistant, is killed with a serrated sickle, and Aidan is found with it. Is Aidan continuing Jonathan's violence?

Aidan is invited to Laura's house for therapy in the chilling finale. However, Joel discovers Aidan is not the troubled teen he thought he was. Instead, Aidan beats Laura and leaves her dead. Joel's long, complicated search for his father's truth ended with this horrific act.

The cycle of violence is complete when Aidan's actions suggest that Jonathan's grandson has inherited his trauma and violence. Aidan apologizes for becoming a killer in the final moments. This revelation raises questions about Joel's family's future and suggests a darker second season.

What was the significance of Jonathan's suicide note

A crucial piece of the puzzle in Lazarus season 1 is Jonathan’s cryptic suicide note, which reads, "it’s not over," accompanied by a drawing of a three-legged stool. Joel learns from Jonathan's death that the note was part of a larger message. The stool symbolizes a dolmen, a tomb associated with death and the afterlife. Joel discovers the truth: Jonathan believed time was cyclical and that his family, especially Joel and Aidan, would repeat his violence.

The note implies that Jonathan's cycle of violence continues. The horrors Joel discovered during his investigation may not be the end, and his family history may haunt him. 

What happens to Alison and the final confrontation

The final confrontation between Joel and Alison is one of Lazarus season 1's most intense. Alison tries to escape her mistake of covering up Jonathan's crimes for years. Alison flees when Joel reveals her role in Jonathan's murders.

A double-decker bus hits Alison after Joel and Seth chase her in a dramatic scene. Her shocking death ends her role in Jonathan's dark legacy. Alison's death lends closure to Joel's investigation but adds to the show's unresolved chaos.

Lazarus season 1 is available to stream on Amazon Prime Video.