More details released in Tomah hotel homicide

Two persons of interest in Tomah homicide investigation in custody
Zachary N. Davis and Sebastian Martinez (AKA Sabrina Martinez)

Two people face multiple charges in the death of a 43-year-old man found dead in a Tomah hotel room.

An autopsy determined Derek M. Magnuson died of multiple stab wounds from a large knife or similar instrument. He was found in a room at the EconoLodge Hotel on March 11 at about 7:30 a.m.

Tomah police said it appears 26-year-old Zachary Davis and 20-year-old Sebastian Martinez, who also goes by several other names including Sabrina Martinez, were at the hotel as guests of Magnuson. Martinez and Davis are in a relationship.

Monroe County District Attorney Kevin Croninger said he would rather not get into how they knew Magnuson.

“Those details will come out,” Croninger said.

During a Wednesday morning news conference, Tomah police gave a timeline of events leading up to Magnuson’s death:

March 5: Davis and Martinez were suspects in a stolen vehicle case in Boise, Idaho. The criminal complaint states Martinez and Davis took a vehicle from a car dealership. Police said they started driving the stolen vehicle across the country towards North Dakota.
March 8: While in Stanley, North Dakota, Davis and Martinez were involved in a high speed police chase. They were able to get away and continued traveling towards Wisconsin. Martinez told investigators they were going to drive to New York.
March 10 at about 5 p.m.: Davis and Martinez stopped in the Woodbury, Minnesota, area. Police said video surveillance shows they both entered a sports store and Davis bought a machete style knife. In the evening, Davis and Martinez are identified in video surveillance at the EconoLodge Hotel in Tomah. They appeared to be guests of the victim. The criminal complaint states Davis admitted to investigators he stabbed Magnuson, stole his wallet and used his debit card and cash from the stolen wallet.
March 11: In the early morning hours, a hotel guest staying in a room next to the victim’s room heard a disturbance coming from the victim’s room. Magnuson was found dead in his hotel room at about 7:30 a.m. At about 7:45 p.m., Davis was identified on video surveillance buying things from a sports store in Hammond, Indiana.

Tomah police said investigators were not able to track the whereabouts of Davis or Martinez after they left the sports store in Indiana.

At the time of the Tomah homicide, Davis and Martinez were wanted by the Idaho Department of Corrections for prior probation/parole violations. The Idaho Department of Corrections updated the warrants making them extraditable and valid throughout the United States, instead of just within Idaho.

March 22: Davis and Martinez were apprehended by authorities in Millersville, Tennessee. Tomah police said they were still in possession of the car stolen from Idaho. Investigators found a machete that appeared to be similar size and shape to the machete purchased in Minnesota in the car.

Davis faces the following charges:

First degree intentional homicide Armed robbery with use of force Operate a motor vehicle without owner’s consent

Martinez faces the following charges:

Felony murder Harboring or aiding a felon Operating a motor vehicle without owner’s consent

“Felony murder is an allegation that while either committing another serious crime or being a party to a serious crime, an individual was killed,” Croninger said. “So the allegation being there that Mr. Martinez was part of a robbery that led to the death of Mr. Magnuson.”

Davis and Martinez are currently being held in the Robertson County Jail in Tennessee. The Monroe County District Attorney’s Office is working with prosecutors in Robertson County to extradite Davis and Martinez back to Wisconsin. There is no time frame for extradition at this time. A permanent address is not listed for Davis or Martinez.