OLD TOWN, Maine — A man allegedly involved in the making of methamphetamine at 178 Brunswick St. died of his injuries after the lab exploded and caught fire on Tuesday and he fled the scene, according to police.

Four others also have been arrested in connection with the illegal meth manufacturing operation.

The body of the man, whom police are not identifying until his family is notified, was found just down the street at 465 Brunswick St. on Thursday, two days after the explosion. Police did not state when, or whether they knew when, he died.

“Residents of the house found the body,” Stephen McCausland, Maine Department of Public Safety spokesman, said Friday.

Investigators with the fire marshal’s office also believe a fire at the apartment at 178 Brunswick St. was caused by an explosion during the manufacturing of methamphetamine and that the man was seriously burned before he fled the scene, McCausland said.

The body has been taken to the state medical examiner’s office in Augusta for autopsy.

Tammy Beaupre, who lives downstairs from the apartment where the explosion took place, said she heard a loud noise, called 911 and then saw a man leaving the four-unit apartment with “blood on his face.”

He left on foot heading up Brunswick Street, she said.

“It’s the same guy that goes in and out of there regularly,” Beaupre said, referring to her neighbors’ apartment.

Officers responding to the 10 p.m. call about the fire on Tuesday detected “a strong chemical smell” in Apt. 3 and found a burned soda bottle in the backyard that they determined had been used to make the methamphetamine, the probable cause affidavit filed at the Penobscot Judicial Center states.

A second burned soda bottle was found in the kitchen, hidden in a file cabinet and wrapped in a plastic bag, and there were burn marks on the floor and the wall of the kitchen, the court documents state.

The “one pot” method of making meth involves mixing certain common household chemicals together with Sudafed or other drugs containing pseudoephedrine, which is “cooked” by adding lithium taken from batteries, according to officials with the Maine Drug Enforcement Agency.

Four people were arrested Thursday in connection with the case.

Jason Smith, 38, and Carrie Ballanger, 31, who lived at the upstairs apartment where the explosion took place, and Don Dube, 47, and Susan Smith, 36, all were charged with aggravated unlawful operation of the meth lab, a Class A felony. Dube and Susan Smith are dating and homeless and have been staying at the apartment, it was announced Friday when the four suspects made their first appearance on the charges at the Penobscot Judicial Center in Bangor.

The charges are elevated because of the heightened danger of the lab being located inside an apartment house, McCausland said.

“The seriousness of this case cannot be understated,” Shelly Okere, assistant district attorney, said in court. “An explosion at an apartment building has a high extent of danger.”

Bail was set at $10,000 for each defendant.

Ballanger said in court that “I was sleep,” and Jason Smith said he understood the charges against him, “but I don’t understand why I’m being charged with this.”

District Court Judge Gregory Campbell told Smith that he needed to discuss that with his attorney.

Law enforcement officers found a slew of items needed to make meth in their apartment, the affidavit states.

The illegal stimulant that has plagued western parts of the U.S. since the 1980s started to creep into Maine about nine years ago, according to Peter Arno, commander of the northern division of the MDEA,

There was one meth lab bust in Maine during 2009, but the number of suspected or confirmed manufacturing operations has since increased every year, with two labs investigated in 2011, eight in 2012, 11 in 2013, 37 in 2014, and 56 in 2015. The number more than doubled in 2016, when 125 manufacturing sites for the addictive drug were investigated.

Less than two weeks ago, one of the state’s largest meth busts occurred in Aroostook County, when an alleged lab was discovered in downtown Madawaska. It was the 15th time MDEA agents were called to respond to a possible meth-making operation this year, according to McCausland. The Old Town incident marked the 20th, he said.

Ballanger’s father, Jim Ballanger, said Friday that he knew about but could do little to stop drugs from entering his daughter’s life. He said that she recently had attempted to get clean.

He stopped by the apartment on Friday morning to find out more about what had happened this week. He said his daughter is enrolled in a methadone program that tests her for illegal street drugs, and to the best of his knowledge she has been in recovery for about two years. The retired military veteran also said, “We’ve dealt with it for years.”

Erik Crocker, the lawyer appointed to represent both Jason Smith and Ballanger on Friday, said both are on methadone provided by the Discovery House and are in the process of trying to reunify with their 20-month-old son. He asked for a lower bail, saying neither would get methadone at the Penobscot County Jail, which discontinued offering methadone to prisoners more than year ago.

The request was denied.

According to court documents, officers found a burned jean jacket with red flannel lining at the site of the explosion they say they believe belonged to the mortally injured man. The jacket was charred on the left arm, the left front and an area on the back.

A woman who answered the door at 465 Brunswick St. on Friday morning declined to comment about the body being discovered there Thursday.

“I’m not going into it,” she said, before slamming the door.