The Oklahoma police detective accused in the mystifying hotel room murder of his department chief — who was also described as one of the investigator's closest friends — was reportedly found sitting on top of Chief Lucky Miller's body "mumbling" incoherently when a staff member first burst into the room.

Officer Michael Nealey, 49, was charged with second-degree murder after the bizarre incident that unfolded Sunday night at a Hilton hotel on Pensacola Beach in Florida.

OKLAHOMA POLICE CHIEF IN FLORIDA FOR CONFERENCE ALLEGEDLY KILLED BY FELLOW OFFICER

Both police officers, of the Mannford Police Department, were visiting the Panhandle to attend a law enforcement conference. The pair, described by the Mannford town mayor as "the best of friends," were seen drinking together that evening, but got into a "physical altercation" just before 10 p.m., the Escambia County Sheriff's Office said.

A disruptive commotion in the hotel room used by Nealey and Miller drew the ire of fellow guests, who called hotel staff before the sheriff's office ultimately got involved. By the time police arrived on the scene, Miller, 44, was dead, his body collapsed on the floor and his face on the ground, WEAR-TV reported. The police chief's face appeared to be bruised and his right eye swollen.

A maintenance worker who had responded to the noise complaint before authorities arrived said he heard a "grunting" noise inside the room and, when he went inside, discovered Nealey on top of Miller. The worker, who wasn't identified, said he pulled Nealey off the other man, causing injuries to Nealey's face when his head hit the ground.

No weapon was found, according to an Escambia County sheriff's spokesperson, but Nealey's hand was reportedly red and swollen. Officials said alcohol was involved and an autopsy was being conducted.

OKLAHOMA POLICE CHIEF, FELLOW COP ACCUSED OF MURDERING HIM WERE 'BEST OF FRIENDS,' TOWN MAYOR SAYS

People staying nearby told investigators they heard laughing, yelling and a "roaring noise" coming from the hotel room Sunday night, according to KJRH. But then something unexplained happened and people reported hearing a voice shout "stop it, Mike," several times -- the noises allegedly grew louder, until they stopped altogether.

Nealey was booked Monday morning at the Escambia County Jail on homicide charges, according to online sheriff's office records. He's being held on a $500,000 bond and is scheduled to appear in court Dec. 5.

Mannford Mayor Tyler Buttram said the two cops were not only coworkers but also close pals: "Where one was, the other one was. They were always together.

“Lucky was a great man, but I’ll be honest, so was Officer Nealey. Those two were the best of friends,” said Buttram, who oversees the city of just over 3,000 people that's roughly 20 miles west of Tulsa. “We ask that everyone pray for both of the families that have been devastated by this terrible tragedy. None of this makes sense, and we are heartbroken as we try to understand how something so tragic could have happened.”

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Miller, who served as police chief since 2007, leaves behind a wife and three children.

The Associated Press contributed to this report.