After only a short deliberation, jurors found Zachary Davis guilty on all three counts related to the homicide of a Tomah man in 2015.
During closing arguments, the state argued Davis planned the armed robbery well before going back to Magnuson's hotel room, where he was eventually killed.
Davis testified Wednesday the victim initiated the fight in the motel room that lead to Davis stabbing him more than seven times. Davis testified it was because he "feared for his life" and acted in self defense.
However, the prosecution disagreed.
"If what he is saying is true, he would have yelled for help," Monroe County District Attorney Kevin Croninger said. "His mindset would not have been, oh my gosh this is causing a lot of noise and I'm going to get in trouble for the stolen car. His mindset would have been, oh my god, this guy is going to kill me, anybody that comes is going to help. That was not his mindset, by his own admission.
The defense used closing arguments to argue the state left out critical pieces of evidence, like a sequin found on the body of Magnuson. The defense said the sequin was identical to those on Sabrina Martinez's top, indicating Magnuson did in fact attempt to sexually assault Martinez.
They also tried to convince jurors Davis had no choice but to fight for his life during the altercation.
"What did they find under Derek Magnuson's fingernails? Derek Magnuson's DNA," said Davis' attorney Christopher Zachar. "Not one cell of Zach Davis was found underneath Mr. Magnuson's fingernails. There's a simple explanation for that. Because those fingernails weren't out in a defensive pose. Those fingernails were curled into fists."
Magnuson's family was in the courtroom when the verdict was read. Magnuson's father thanked Croninger after the conviction as well as the investigators that testified on the state's behalf.
"Mr. Davis paid back Mr. Magnuson's kindness by stabbing him in the back and robbing him and leaving him on the floor to die, flopping like a fish," Croninger said.
Davis, 27, was charged with First Degree Intentional Homicide in the stabbing death of Derek Magnuson.
The jury found also found Davis guilty of Armed Robbery with Use of Force and Driving a vehicle without Consent.
27-year-old Zachary Davis took the stand in his own defense during the eighth day of his homicide trial in Monroe County.
Davis is charged with first degree intentional homicide in the death of 43-year-old Derek Magnuson, who's body was found at the Econo Lodge in Tomah in March 2015.
On Wednesday, Davis took to the stand looking to convince the jury he stabbed Magnuson in self defense.
Davis testified he met the victim in a parking lot in Tomah and went to have a drink with him at the Best Western. Then, he says the victim invited him back to his motel room to hang out.
After showering, Davis testified he came out of the bathroom to find Magnuson making a pass at his transgender girlfriend, Sabrina Martinez. After telling Magnuson to stop and threatening to leave, he said Magnuson charged at him.
"He was seated and when I reached down to pick up my shoes, he basically blitzed off the bed and tackled me," Davis testified.
Davis said a struggle ensued for several minutes and he soon realized Magnuson wasn't letting up.
"I was getting terrified at that point," he said. "Just the way my head was feeling at that point and this guy was not letting up on me. I was like, when is this going to stop?"
Davis said fearing for his life, he had no choice but to reach for his machete he had packed in a bag. He then stabbed Magnuson on his back near his right shoulder, but said Magnuson continued to fight him.
"After I stabbed him the first time, the machete flew out of my hand. We both looked at it and were thinking the same thing. Then we both darted at it and after a struggle I got the upper hand and took it from him."
Despite regaining control of the machete, he testified Magnuson kept fighting him.
"My intentions were not....it was more like get away from me type stuff," Davis testified. "It wasn't like, I'm trying to drive this thing all the way through you it was like I just want you to get away."
Davis said he and Sabrina Martinez quickly left the motel after the fight, not knowing if Magnuson was dead.
He also admitted to stealing the victim's wallet and debit card out of spite.
Closing arguments are scheduled for Thursday. The prosecution contends the entire incident was an armed robbery gone wrong.
If convicted, Davis faces life in prison.