It was a hotter than usual Thursday morning in July when a curl of gray smoke began to rise over the treetops in Graham Andoe’s backyard.

It appeared to be coming from the home of Roger and Dorothy Abbott, close friends whose home on Peeler Road in Dunwoody backed up to the Andoes’. Other nearby residents noticed it, too, and called 911 to report a fire.

Before the afternoon of July 1, 2010 was over, the bodies of the Roger and “Dot” Abbott, 82 and 78 respectively, were pulled from their home’s charred interior. Police said it was clear the couple had been killed and their house torched in an attempt to destroy the evidence.

At first it was a puzzling whodunit for the new city’s fledgling police department, which was then barely a year old.

Now, police believe they know who did it, but don’t have enough evidence to make an arrest. They remain quiet about many details about the case, including how the couple died and what the motive was.

To neighbors and friends, it feels like the investigation has stalled.

“We are still waiting for the Dunwoody police to make their promised arrest,” Andoe said. “I’m afraid the way this is dragging, they may not ever get the evidence.”

Five months after the slayings, police met with neighbors at the nearby Village Mill community pool and assured them an arrest was imminent, Andoe said.

Connie Alonso, whose daughter lives near the Abbott home, saw the fire and remains unnerved by the slayings.

“I think about it all the time when I come by,” Alonso said.

The Abbotts’ house, now boarded up and unoccupied, is barely visible beyond the blossoming apple trees and vegetable garden in Andoe’s backyard, where the retired Pan Am pilot puttered about in denim overalls one day last week. Andoe said he knew the Abbotts for three decades, having shared a fence line with them.

Once a month, he and Roger shared a breakfast table with the Retired Old Men Eating Out (ROMEO) group to which they both belonged.

Roger, a retired chemical engineer, and Dot, a housewife who had raised their four children, were “salt of the earth” people, Andoe said. Roger collected Bibles. Dot cared for a mentally disabled adult son whom she had birthed later in life. That son was away at camp the week the Abbotts were killed.

The other Abbott offspring have repeatedly declined media requests for interviews. They did not return calls seeking comment last week.

Dunwoody police said a lack of evidence has been a big barrier to solving the case. What crime scene evidence the blaze did not destroy, firefighters damaged in their attempts to quench the blaze. And nobody they spoke with could fathom a motive.

“There was not one bad word that’s been said about the Abbotts,” said Sgt. Mike Carlson.

Nevertheless, investigators believe the killer knew the couple. There was no sign of forced entry and no belongings appeared to have been removed from the house.

A passer-by saw a man walking in the front yard the morning of the fire. He was a white male of average height and weight between, age 40 to 45, with sandy red to brown hair, wearing a light colored T-shirt.

Police released the sketch of the “person of interest” in December and again this month, but received no new tips from the public.

The Abbotts attended Peachtree Presbyterian Church in Atlanta for 33 years and were devoted members of the AGAPE Sunday school class. At their funeral, the Rev. Vicki Franch led the congregation for the first time in her career in prayer for justice, asking God to give police discernment, energy and courage. She offered this prayer for the killer:

“Lord, may your hand be upon the person who did this to them.

“May they not rest in body or spirit until they confess their sin.

“May they take no pleasure in life until they confess.

“May they profit in no way from their sin.

“Lord, pursue them and stop them from any further violence or evil.”

If you have information about the deaths of Roger and Dorothy Abbott, contact Dunwoody Sgt. Gary Cortellino at 678-382-6908 or gary.cortellino @dunwoodyga.gov. You can submit an anonymous crime tip at www.dunwoody police.com.