Updated

A Mississippi state official said Tuesday that a preliminary investigation into a Tennessee man’s death indicates no police misconduct despite a witness claiming officers hogtied the man face-down on a stretcher hours before he died.

Memphis chemical engineer Troy Goode, 30, died in a hospital Saturday, two hours after being detained by the Southaven Police Department, according to multiple news outlets.

Tim Edwards, a lawyer for the Goode family, told The Associated Press Tuesday, "Positional asphyxiation is what we believe was the most likely cause of death."

Edwards told The Associated Press he has hired a forensic pathologist to complete an independent toxicology report. He didn’t name the pathologist. Edwards said the medical examiner in Jackson has completed an autopsy and the body has been released to Goode’s family.

The district attorney asked by the Southaven Police Department to complete an independent investigation of Goode’s detention said he was told by DeSoto County Coroner Jeffrey Pounders on Tuesday that preliminary autopsy findings show Goode likely died of “either a heart or lung condition.”

John Champion told The Associated Press that “unless something changes” with the autopsy findings, he is going to conclude “there was no misconduct on behalf of police.”

Pounders is the official who ordered the autopsy, according to Champion, who confirmed that the autopsy was conducted by the state medical examiner's office in Jackson. Champion said it will be weeks before a final toxicology report is ready.

Goode and his wife, Kelli, had been on their way to a Widespread Panic concert in Southaven that night. Edwards said Goode and his wife were in the parking lot of the concert when they decided to leave. They then stopped at another parking lot, near a restaurant. He said Goode had taken a small amount of LSD. He said other “participants” in the drug didn’t experience any trouble.

Southaven Police Chief Tom Long had said authorities were called into the parking lot and emergency personnel detained Goode and took him to Baptist Memorial Hospital-DeSoto, where he died a few hours later.

"Officers were informed that the individual acting erratically was doing so on an alleged LSD overdose," Long said.

David McLaughlin, a Memphis attorney, told the Jackson Clarion-Ledger that he witnessed and posted a video of the arrest on YouTube, saying it shows Goode being restrained, face-down on a stretcher with his legs pulled back and bound.

"Paramedics arrived on scene, and I see them put him in a four-point restraint or hogtie, I don't know how else to describe it," McLaughlin told the newspaper.

McLaughlin added, "He looked to me like he was struggling or convulsing or both. He appeared to be in distress to me."

The video posted by WREG-TV, a Memphis station, appears to have been shot from across the parking lot and shows a man, who McLaughlin claims is Goode, on a gurney being loaded into an ambulance.

Long said in an email that Goode was "acting strange and not cooperative." He added, "Officers attempted to detain the subject who began to resist and run from them again."

Long said in his statement that paramedics took Goode to the hospital for treatment for a possible drug overdose. Long said a toxicology report may take two months. He said an autopsy was conducted in Jackson.

Asking about the hog-tying incident, Southaven police spokesman Lt. Mark Little told news media outlets that "it's nothing that's illegal."

"It's called restraining."

"We're just basically keeping him from kicking and hurting someone," Little said.

Edwards said the family is distraught and looking for answers, but they are not jumping to conclusions. Family members are not commenting because they are "not in the frame of mind" to do so.

Edwards said Goode was 6-foot-1, 145 pounds and a "rail thin," intelligent man who worked as an engineer for nexAir, a distributor of atmospheric gases and welding supplies based in Memphis. He said Goode graduated with honors from Christian Brothers University in Memphis.

"This guy was exceptional. He was quite bright," Edwards said.

"He was not a criminal," Edwards added. "He was a highly compensated individual who made a mistake, and now he's dead because of it," Edwards said.

The Associated Press contributed to this report.