The dead man had ordered a bacon cheeseburger.

A receipt from that meal was the unlikely clue that police said helped them unlock the mystery behind a fatal June 9 shoot-out in a suburban Montgomery County home and led to the arrest of two men in the attack.

Montgomery County District Attorney Risa Vetri Ferman and Upper Gwynedd Township Police Chief David Duffy announced charges Tuesday against two men who they say traded gunfire with Jermaine Edwards inside his North Wales home three weeks ago.

The defendants, Niochie B. Lawson, 23, of Laurel, Md., and Jakel Stone, 20, of Hyattsville, Md., face charges of conspiracy, robbery, and related offenses. Both have extensive criminal records.

Prosecutors have said Edwards, a 30-year-old with his own record of drug dealing, was clearly the target of the attack, though they have declined to say why.

But a probable-cause affidavit filed in Montgomery County hinted at one possible reason: It says one of the men came to Pennsylvania expecting to reap $150,000 in a robbery.

The affidavit, filed by Upper Gwynedd Detective Raymond Royds and Montgomery County Detective Mark Minzola, also offered the most detailed account yet of the investigation to crack the case. It charts cooperation from at least four law enforcement agencies and revealed the sleight of hand between Edwards and his wife that led to the fierce firefight.

According to the document, Edwards was driving to his Hancock Road house with two of his three daughters about 10:20 p.m. that Wednesday when his wife, Jolene, called him to say a security alarm on their outside shed was beeping. Edwards told her to grab his 9mm Glock handgun and wait for him to come home.

She then slid the weapon into her robe pocket, the affidavit said.

As Edwards pulled up, at least four men emerged from behind the shed and forced him and his children into the house, police say. Each of the men wore yellow latex gloves.

Once inside, the armed intruders ordered Edwards' wife and daughters to go upstairs, according to the affidavit. Before they did, Edwards allegedly slipped behind his wife and removed the gun from her pocket.

Moments later, the gunfire erupted. At least 22 shots from three guns were fired in the kitchen and living room, police said.

When officers arrived, they found Edwards, with wounds to his leg and chest, and a dead intruder.

The dead man had no identification. But police said that in his pocket, they found a receipt from a Roy Rogers restaurant at the Maryland House rest stop on I-95. The receipt was for a bacon cheeseburger and fries, bought about three hours before the ambush.

The next day, detectives obtained surveillance video from the rest stop and saw the cheeseburger purchase, their statement said. They also saw the man in another video frame - this time with two associates at a Cinnabon stand. One wore a black shirt sporting the number 3.

Meanwhile, relatives of the dead man saw news reports of the shoot-out and came to Montgomery County to identify him as Kieme Persons, 22, of Capitol Heights, Md.

At the same time, investigators enlisted a confidential witness who knew Persons - and the man he accompanied to Philadelphia, Niochie Lawson. The witness said she had talked to Lawson, who denied any knowledge of Persons' death.

He allegedly said that he and Persons split up in Philadelphia because Persons "had his own move to pull worth $150,000." Lawson also admitted he had been shot, but said it was in an unrelated incident.

Working with Philadelphia police, investigators then discovered that two men had been treated for gunshots the night of the shooting at Albert Einstein Medical Center.

In the emergency room, the patients gave false names and what police called "an implausible story" to explain their injuries. Detectives later determined the men to be Stone and Lawson.

Then detectives watched the hospital surveillance video, noting that Stone had arrived at the ER wearing a black shirt with a 3 on it.

They also examined the bullet that emergency room staff pulled from Lawson's leg. It matched the Edwardses' 9mm Glock.

Not far from the hospital, police found what they believe was the getaway car, an abandoned blue Cadillac. Inside, investigators found duct tape, cell phones, and bloodied yellow latex gloves, the affidavit says.

Stone was arrested as he recuperated at the hospital. Lawson was picked up Friday in Maryland, and is awaiting extradition to Pennsylvania.

At least one person involved in the shoot-out remains on the loose, authorities said. He has not been identified.

Edwards was released after eight days in the hospital. Ferman said he would not face charges because he was "legally justified in the use of deadly force" to protect his home.

The district attorney hailed what she called "outstanding police work" by the investigators.

"They have been absolutely dogged in their pursuit of those responsible in this home invasion," she said.

Contact staff writer John P. Martin at 610-313-8120 or jmartin@phillynews.com.