Joseph Albert Sonnier and Becky Murdered by David Neil Shepard, Ferman Galagos, and others, Lubbock, Texas, United States
This source-based behavioral analysis does not establish a clinical diagnosis, motive, or legal finding.
The case involves intense obsessive attachment, romantic rival elimination, and proxy solicitation. Following the end of his extramarital affair with Richelle Shetina, Dr. Mike Dixon displayed severe emotional fixation and entitlement, refusing to accept the termination of the relationship. Distressed by Shetina's new romantic bond with Dr. Joseph Sonnier, Dixon utilized David Shepard to perform covert surveillance, character assassination, and ultimately physical elimination of his rival.
Dixon demonstrated possessive and manipulative control dynamics toward Shetina, expressing feelings of betrayal after ending his own marriage for her. When Shetina formed a healthy attachment with Sonnier, Dixon perceived Sonnier as a direct obstacle to his emotional reclamation, leading to proxy stalking and contract murder.
The dynamic escalated from severe romantic dissatisfaction and obsession into covert third-party stalking and harassment, ultimately culminating in contract homicide when indirect breakup tactics failed.
Each entry separates the reported behavior or state from the analytical strength of the available narration.
| Behavior / construct | Person / subject | Detailed case context | Evidence |
|---|---|---|---|
| Jealousy Emotional state | Thomas Michael Dixon Suspect |
Dixon experienced severe hostility upon learning Shetina had moved on with Sonnier. His intense jealousy prompted him to engage Shepard to actively monitor and disrupt their partnership. Context or trigger: Learning that Richelle Shetina had initiated a serious relationship with Dr. Joseph Sonnier. Reported expression: Intense distress, hostility toward Sonnier, and obsession with forcing a breakup. |
Narrative-supported psychological state Confidence: High |
| Rumination or fixation Cognitive pattern | Thomas Michael Dixon Suspect |
Dixon remained fixated on Shetina long after their separation, writing emotional messages claiming he sacrificed his family for her and devoting substantial effort to monitoring her life. Context or trigger: The termination of his affair with Shetina and her subsequent relationship. Reported expression: Persistent obsession with Shetina and repeated attempts to control her romantic choices. |
Narrative-supported psychological state Confidence: High |
| Premeditation and planning Planning or impulsivity | Thomas Michael Dixon Suspect |
Dixon engaged in deliberate advance planning by providing Shepard with silver bullion and a firearm, establishing communication protocols to execute the lethal plan. Context or trigger: Failure of initial harassment tactics to cause a breakup between Shetina and Sonnier. Reported expression: Procuring a weapon, arranging financial compensation in silver, and directing Shepard to commit murder. |
Narrative-supported psychological state Confidence: High |
| Instrumental aggression Offender behavior | David Neil Shepard OffenderHired Suspect/Offender |
Shepard acted as an instrumental executor, traveling to Lubbock, stalking Sonnier's residence, and violently eliminating him in exchange for monetary gain. Context or trigger: Offer of financial payment in silver bars by Dixon. Reported expression: Executing a lethal attack on a stranger solely for financial compensation. |
Narrative-supported psychological state Confidence: High |
| Deception or concealment Behavioral pattern | Thomas Michael Dixon Suspect |
Dixon actively engaged in concealment behaviors after the crime, denying he knew Sonnier, jumping into a pool with his phone, removing the SIM card, and texting Shepard to hide. Context or trigger: Police investigation following the discovery of Sonnier's body. Reported expression: Denying knowledge of the victim, attempting to destroy digital evidence, and instructing Shepard to lay low. |
Narrative-supported psychological state Confidence: High |
| Possessiveness or monitoring Control dynamics | Thomas Michael Dixon Suspect |
Dixon exhibited extreme possessiveness by commissioning covert surveillance of Shetina and Sonnier, attempting to intrude into their private routines and gym visits. Context or trigger: Shetina entering a new relationship with Sonnier. Reported expression: Hiring a proxy to photograph, track, and send unwanted letters to Shetina. |
Narrative-supported psychological state Confidence: High |
Select a stage to expand it; scroll horizontally to follow the full sequence.
Dixon engaged in an extramarital affair with Shetina, leading to his divorce and a subsequent volatile relationship that eventually ended.
Upon learning Shetina was dating Sonnier, Dixon experienced intense rejection and fixation, perceiving Sonnier as a romantic rival.
Dixon contracted Shepard to spy on Sonnier, take covert photographs, and attempt to frame Sonnier for infidelity.
When disruptive tactics failed, Dixon provided Shepard with silver bars and a handgun to execute Sonnier.
Arrows show the sequence described in the source narrative; they do not prove that one psychological state caused the next event.
Analysis is based on public trial records, police statements, and media transcripts; no formal clinical psychological evaluation of the participants is available.