Following Alleged Homicide, Defendant’s Toxicology Report Detected Opioids and THC

A Flathead County jury on Tuesday heard final witness testimony in the case against 49-year-old Jeffrey Scott Serio, who is standing trial for deliberate homicide in the death of 67-year-old Raymond Maurice “Mory” Grigg after allegedly driving over him in an Evergreen cornfield on Aug. 19, 2025 after the victim fired multiple gunshots at him.

On the seventh day of trial during the state’s rebuttal, the jury heard from Montana State Crime Lab Forensic Toxicologist April Sheets, who told jurors Serio’s blood sample test revealed levels of the opioids buprenorphine and norbuprenorphine, lorazepam and THC.

“The buprenorphine is what we call scientifically the parent drug, it’s the main component and norbuprenorphine is the metabolite,” Sheets said.

Sheets said buprenorphine and norbuprenorphine are categorized in a drug class of narcotic analgesic, which affect opioid receptors and suppress the central nervous system.

While she confirmed norbuprenorphine can have a psychoactive side effect, Sheets also said buprenorphine’s general effects can include memory loss, drowsiness, warmth, sweating, drowsiness and confusion.

Sheets also told the jury THC can cause effects like increased disorientation, drowsiness, panic reactions, anxiety and paranoia.

Combined, Sheets said the drugs can enhance depressing effects like lowering a person’s heart rate, blood pressure and breathing rate while also decreasing alertness.

“If a person is not as alert as normal, they may not perceive things as they normally would,” Sheets said.

Prior to Sheet’s testimony, the jury heard from public defender Alisha Rapkoch’s final witness, firearms expert Steven Howard, who conducted a trajectory analysis on the Toyota Sequoia Serio was driving during the alleged incident.

In the analysis, which was not conducted at the scene, Howard told the jury he found two bullet marks and one bullet hole in the front of the vehicle. He also said he used a trajectory rod to calculate the maximum distance a shooter could have been from the two strike holes, which he concluded was “plus or minus” 11-and-a-half feet away.

But during cross examination, prosecutor Ashley Frechette questioned the expert witness’s methods and said he made assumptions about the surface the vehicle was resting on along with the shooter’s position when the gun was fired.

Howard told the jury he estimated the trajectory based on Grigg’s 6-foot-2-inch stature as if he were holding a gun at shoulder height, which Frechette described as an assumption.

The expert witness defended the scenario as irrelevant, saying it was not possible that the shooter was further than 11-and-a-half feet away based on his trajectory rod method.

“He could have been closer,” Howard said. “How much closer? I don’t know. But he couldn’t have been further away.”

At the end of cross examination, Frechette questioned the validity of Howard’s trajectory analysis and said he had been excluded as an expert witness in multiple states for using unreliable methods, which he confirmed.

After the defense rested, the state brought Flathead County Sheriff’s Office crime scene team member Kate Wride back to the stand during a rebuttal, where she testified that she did not perform a trajectory analysis on the vehicle because it was removed from the scene.

“When you move that vehicle from the spot where it was impacted or removed it from the scene altogether, any trajectory analysis is not going to be accurate,” Wride said. “There are multiple factors that can affect the trajectory and trajectory analysis.”

For example, factors like the angle of the vehicle and the shooter’s position were unclear while sizing discrepancies between the bullet holes and the trajectory rod would have added complications and caused an inaccurate calculation, she said.

“There [were so many] unknowns and other factors that we just didn’t know,” Wride said.

Closing arguments begin tomorrow at 9 a.m. in Flathead County District Court.

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