← Back to United States casesLizzy Mario Disappearance Involving Set Mazala, Kate McDonald, and others, Chester, New Hampshire, United States
Case Summary
Lizzy Mario, a 19-year-old marine biology student living with her uncle Tony and his wife Becky in Chester, New Hampshire, disappeared on October 9, 2012. She had gone to visit her friend Kate McDonald, who lived with her boyfriend Set Mazala. During a night involving a threesome and BDSM activities, Set Mazala strangled Lizzy to death. Kate McDonald witnessed the murder but did not intervene due to fear. The body was wrapped and disposed of in a river, but never recovered. Set Mazala was arrested, charged, and convicted of first-degree murder and sentenced to life imprisonment without parole. Kate McDonald was charged with obstructing justice and served three years in prison after a plea deal. The case involved coercive control, manipulation, and a dominant-submissive relationship dynamic between Set and Kate. Lizzy's parents rejected the accidental death narrative and continue to seek justice for their daughter.
Basic Information
Country: United States
State/Province: New Hampshire, United States
City/Region: Chester
Incident Type: Murder
Relationship Status: Unknown
Relationship Duration:
Incident Date: Oct. 9, 2012
Relationship Journey
Relationship Origins:
- Met at Workplace
- Friends circle
Relationship Stages:
- Dating
- Living Together without Marriage
Analysis
Contributing Factors:
- Domestic Conflict
- Family pressure
- Suspicion of infidelity
Red Flags:
- Secretive communication patterns
- Escalation Pattern / Violence
- Manipulative behavior
- Threats
- Mental Health Deterioration / Hopelessness
Motives:
- Revenge
- Jealousy
- Control/domination
- Eliminate romantic partner
Relationship Outcomes:
- Divorce filed
- Legal case ongoing
- Homicide during marriage
- Arrest made
- Relationship ended
People Link Graph
Relationship Journey Graph
Origin
- Met at Workplace
- Friends circle
How the relationship or connection began.
Status
- Unknown
Stages
- Dating
- Living Together without Marriage
Important relationship phases recorded for this case.
Warning Signals
- Secretive communication patterns
- Escalation Pattern / Violence
- Manipulative behavior
- Threats
- Mental Health Deterioration / Hopelessness
Reported red flags or early concern points.
Pressure Points
- Domestic Conflict
- Family pressure
- Suspicion of infidelity
- Revenge
- Jealousy
- Control/domination
- Eliminate romantic partner
Contributing factors and possible motives from the available sources.
Incident
2012-10-09
Outcome
- Divorce filed
- Legal case ongoing
- Homicide during marriage
- Arrest made
- Relationship ended
Recorded relationship or case outcome.
Sources
English labels are shown first. Original-language titles are preserved for source verification.
Lizzy Mario Disappearance Involving Set Mazala, Kate McDonald, and others, Chester, New Hampshire, United States
MR POARO - Iran · Original language: English
View original title
The Disappearance and Death of Lizzy Mario
AI Intelligence Assessment
Relationship Pattern
Coercive Control
Pattern Analysis
The relationship involved a dominant-submissive dynamic between Set Mazala and Kate McDonald, characterized by coercive control, manipulation, and threats. Lizzy Mario was introduced into this dynamic under false pretenses, leading to her murder. The pattern shows escalation from control and intimidation to lethal violence, with complicity through fear and coercion.
Investigative Notes
Police interrogated all involved parties, focusing on Set Mazala and Kate McDonald. Forensic evidence included DNA on clothing and discovery of black leather gloves used in the murder. Kate's initial denial and later confession under plea deal were critical. Set was convicted of first-degree murder and sentenced to life imprisonment. Kate was sentenced to three years for obstruction. The victim's body was never recovered despite extensive searches.
Investigation Confusion
Initial conflicting statements from Kate and Set about Lizzy's presence and events. Set's narrative of accidental death was disputed by prosecution and Kate's later confession. The absence of the body complicated the case. Defense argued accidental death during consensual sexual activity, while prosecution emphasized intentional murder.
Case Reconstruction / Puzzle Pieces
Lizzy Mario visited Kate McDonald’s apartment on October 9, 2012. Set Mazala joined them, and after playing strip poker, a BDSM activity involving tying Lizzy with a rope was initiated. Set strangled Lizzy deliberately, and Kate witnessed but did not intervene due to fear. They disposed of the body in a river. Subsequent investigations revealed coercive control by Set over Kate, and forensic evidence linked them to the crime. Kate eventually confessed under a plea deal, and Set was convicted.
Risk Assessment
High risk due to documented coercive control, threats, and prior violent behavior by Set Mazala. The presence of a submissive partner under control and a third party introduced without full disclosure increased vulnerability.
Key Takeaways
Warning signs include coercive control, manipulation, and secretive relationships. The case highlights dangers of introducing third parties into controlling relationships without full disclosure. Fear and intimidation can silence witnesses and accomplices. Forensic evidence and witness testimony are crucial in overcoming denial and deception.
AI Case Q&A
What early signals mattered most?
Kate's personality change after starting relationship with Set, her limited contact with family, and Set's controlling behavior were early signals.
Which clues helped connect the case?
Kate's initial denial, Set's contradictory statements, forensic DNA evidence on clothing, and Kate's eventual confession helped connect the case.
Which evidence types appeared strongest?
DNA traces on clothing, discovery of black leather gloves, witness testimonies, and recorded interrogations were strongest evidence types.
Witness / Eyewitness Statements
Friends reported Kate's personality change and Set's antisocial behavior. Catherine Fish, Set's ex-girlfriend, testified about his violent tendencies. Acquaintances Roberta Green, Kane, and Paul Hickok witnessed Set's behavior post-incident. Nate McKinney provided information on Lizzy's last known whereabouts.
How did follow-up reports change the understanding?
Kate McDonald initially denied involvement but later confessed under a plea deal, changing the understanding of her role. Set's escape plan and further criminal intentions were revealed during investigation.
What remained unclear?
Lizzy Mario's body was never found, leaving some questions about the exact circumstances of disposal and final resting place unanswered.