One of the two defendants charged with the murder of 19-year-old Jerry “Mike” Clayton on July 6, 2016 and setting the mobile home he shared with his father ablaze pleaded guilty Aug. 18 to first-degree murder, first-degree burglary and first-degree arson.

Judge Cheryl Carey will set a sentencing date later this month for Sebastian Gregg in courtroom 3F of the Maleng Regional Justice Center in Kent.

Gregg was charged as an adult under Washington state’s automatic adult jurisdiction law, which allows for prosecution in adult court for 16- and 17-year-olds who are accused of serious, violent offenses.

The murder and burglary charges carry firearm enhancements, and Gregg faces a sentencing range of up to 41 years and two months.

Gregg’s co-defendant, Dylan Mullins, is scheduled for trial on Sept. 5.

Here is a summary of what happened, according to court records and the Auburn Police Department’s statement of probable cause.

Seeing smoke and flames at about 11:35 a.m. July 6, a neighbor called 911. The first fire crews on scene observed that the home was engulfed in flames, and determined it would be unsafe for anyone to enter.

When Clayton’s father arrived, fire raging and his son’s whereabouts as yet unknown, he told police that nothing in the house would have caused an explosion, but that he owned seven weapons that should have been inside the locked gun safe in his bedroom. One of the keys for the safe was on his person, Clayton Sr. told police, the other was in the safe.

When the house — its roof destroyed and only some of the shell and framing still visible — was safe to enter the next day, according to the statement, a fire investigator found, three feet from the sliding back door, three shell casings and the stock of a lever action rifle that had been destroyed by the fire.

Six feet inside, according to the statement, the investigator saw a human foot protruding from the debris.

Clayton’s father said there was no way a weapon should have been near the back door, but he had left a 30/30 lever action rifle in the locked gun safe.

When police found the gun safe, the door was off, and it was empty. Mr. Clayton told police he had last looked in the safe before he left for work at 5 a.m. on the day of the fire. At that time, he said, it had contained a .357 revolver, a .303 Brit rifle, a 30-06 rifle, a 30-30 rifle, a .22 long rifle pellet gun, a .44 black powder revolver and a .50 caliber black powder muzzle loader, and none of the weapons were loaded.

According to the statement, police searching the surrounding property, which backs up to Highway 18, found several man-made trails. Along one nearby trail police found a fully-loaded .357 handgun in a holster and a throwing star nearby. Mr. Clayton identified his handgun.

On July 7 authorities executing a search warrant on the house recovered a body, the 30/30 rifle, some cans consistent with accelerant and a spent 30/30 rifle casing inside of the rifle.

A King County Medical Examiner autopsy later conducted on Clayton’s body identified four bullet wounds, consistent with having been fired upon from both sides with two different caliber firearms.

According to the police statement, Clayton Sr. told police his son had admitted to him that he and a friend had burglarized a relative weeks earlier. Shortly after the burglary, Mr. Clayton said, his son, one of Mike’s cousins and Dylan Mullins took the guns and went shooting in Greenwater. During that outing, according to the statement, Clayton and Mullins got into a fistfight in which Mullins received injuries that required stitches.

The morning of the July 6 fire, according to the statement, a friend of Clayton’s had driven him to the home he shared with his father to pick up some batteries.

According to the statement, when Clayton returned to the car, he told his friend he had forgotten something and returned to the house. As he entered, the friend later told police, she heard someone say, “Oh, s…,” followed by eight to 10 gun shots, or pops.

When the sounds stopped, according to the statement, the young woman saw someone close the front door. From her car, according to the statement, she texted Clayton, asking what he had just “set off in there?” but he did not answer. She said that seven minutes passed before she saw smoke coming from the closed front door and heard a beeping like a smoke alarm. At that point, she drove down the road to a neighbor’s house to ask for help. The neighbor called 911.

After the fire, according to the statement, one of Clayton’s friends found Gregg’s wallet near the trails and turned it over to police.

After shooting the victim and setting fire to the home, according to the statement, Mullins and Gregg stole a truck from the Kent Parks Department and drove it to Grays Harbor County.

When a police officer stopped them in Aberdeen for speeding, according to the statement, the officer ran the plate and learned the truck had been stolen. According to the statement, Mullins and Gregg gave the officer consent to search the truck and their backpacks. In the truck, the officer found guns that had been stolen from the burned home. Police arrested the two and took them to the Grays Harbor County jail in Montesano.

During an interview at the jail there, according to the statement, Mullins allegedly told Auburn Police detectives that he and Gregg had planned the night before to enter the trailer, wait for Mike to come home, and “take him down.”

According to the statement, Mullins told police his intent had not been to kill Clayton but to scare him by grazing or shooting him in the knee, but that Gregg said they should just kill him.

According to the statement, the two entered through Mike’s bedroom window and waited several hours for him to arrive home. When he came inside, according to the statement, Mullins was sitting behind the doorway with the .357 handgun he had loaded. According to the statement, Mullins told police that Gregg shot first but missed, and that he, Mullins then fired the .357 at Clayton. Mullins told police that Gregg fired again, and he heard Mike gurgling, and that he, Mullins, believed it was “a lung shot.”

According to the statement, Mullins said he knew they were going to burn down the house anyway, and Clayton was going to bleed to death or die of burning, so he fired four more bullets into him.