Tomah Police Department homicide press release update

Release Date: ​March 23, 2015


Incident Type: ​Death Investigation - Homicide


Incident Date:​March 11, 2015


Incident Location:​City of Tomah


Incident Victim:​Derek M. Magnuson (43-years-old)​



On March 11, 2015 at approximately 7:30 a.m. Tomah officers responded to a medical call at the Econo Lodge Hotel located at 2005 N. Superior Avenue in the City of Tomah.   


The responding officers and paramedics discovered an unidentified deceased man in one of the rooms.  Subsequent investigation confirmed the male’s identification as that of Tomah resident, DEREK MAGNUSON.


The cause of death, although not known, did appear suspicious and not of natural causes.  An autopsy was ordered by the Monroe County Coroner and completed at the University of Wisconsin Hospital – Madison on Thursday, March 12, 2015.  The preliminary findings of the autopsy are that DEREK MAGNUSON was the victim of a homicide.  The autopsy revealed that the cause of death was the result of penetrating trauma to the body from a knife or a similar pointed object.


Early in the investigation evidence gathered at the crime scene identified two persons of interest as being involved in or having knowledge of this homicide.   The two persons were identified as: 


Zachary N. Davis





196 lbs.

Eyes- Blue

Hair – Sandy or Brown


Sebastian (NMI) Martinez, AKA Sabrina Martinez





120 lbs.

Eyes - Brown

Hair - Black


Sebastian Martinez, who is known to dress as a female, is also known as Sabrina Martinez.  


It is was determined that Davis and Martinez left the City of Tomah and the State of Wisconsin soon after the homicide.  Neither has ties to the Tomah area and were believed to be passing through Tomah at the time of the homicide.  


At the time of the homicide Davis and Martinez were wanted by the Idaho Department of Corrections for prior Probation/Parole violations.  The warrants were valid within the State of Idaho only.  The Idaho Department of Corrections updated the warrants making them extraditable and valid throughout the United States.  


Information was sent out to law enforcement agencies across the nation to be on the lookout for Davis, Martinez and the vehicle that they had been operating in.  


On March 22, 2015, Davis and Martinez were apprehended by authorities in Millersville, Tennessee.  Both subjects were apprehended on the Probation/Parole warrants.  Martinez and Davis are currently incarcerated in the Robertson County Jail.  


The Monroe  County Joint Investigative Task Force has been and will continue working on this investigation.  Maintaining the integrity of this case will benefit investigative efforts moving forward.   Further details of the on-going investigation will be released when appropriate.

Tomah Police