DALLAS (CBSDFW.COM) – Dequin Montgomery has had to chart his own path in life.

After his mother was violently ripped from him, he’s learned to go it alone.

The memories remain, though.

They’re mostly the smaller things that people tend to take for granted. The things that feel so natural they get tucked away.

He mentions the way his mother’s face lit up after he finished a drawing. The way she helped him color, or welcomed him in from playing outside.

Those linger.

“It’s the little things; like someone that actually believes in you as you’re doing things,” Montgomery said. “But now it’s as if … all I remember is what happened to her.”

But her violent, tragic end is starting to dominate the picture.

Montgomery is 47-years-old now. But what happened 41 years ago is what shook his world.

“You don’t know what death is at six years old,” he said. “It still haunts me.”

Montgomery’s mother, Carolyn Montgomery, worked as a cocktail waitress at an upscale North Dallas country club to support herself and her son.

They lived in a nicely kept two-bedroom apartment at what was then called the Sherwood Forest Apartments off Northwest Highway.

She was kind, pretty and young –– but her and her son’s futures were stolen on August 8, 1971.

“She comes home late at night, sits down in her apartment,” said Lt. David Pughes, who oversees homicide cases for the Dallas Police Department. “She’s just relaxing after a long night’s work.”

Then the 20-plus year veteran continued: “What we don’t know is at some point someone comes to the apartment.”

Someone stabbed Carolyn Montgomery and left her to die on the floor of her own living room.

“We believe that the knives used were just regular kitchen knives from her kitchen,” said Pughes. “When police arrived you had the larger knife still in her throat and the smaller knife in her abdomen area.”

The stab wounds were extensive; portions of her body were mutilated.

“It makes you think there was something very personal going on inside the mind of the killer,” Pughes said.

Carolyn was murdered while six-year-old Dequin was sound asleep in the back room. He didn’t hear a thing.

And while the boy slept, the killer draped a blanket over Carolyn Montgomery’s lifeless body and fled.

When Dequin wandered into the den the next morning, he thought his mom was asleep.

“There was a blanket and everything else,” said Dequin Montgomery. “I thought she’s sleeping on the floor so I went out to play.”

When he came back inside, his mother was still hidden under the sheet. He sensed something was wrong and ran to a neighbor for help.

“The neighbor came over and she just screamed,” said Montgomery. “She grabbed me and I remember her holding me, holding me; holding me so tight.”

But the killer left a piece of evidence in plain sight that’s haunted investigators for more than 40 years. It’s only five words, but they’re never far from Dequin Montgomery’s mind.

“The note says, ‘The wrong one I’m sorry,’” said Lt. Pughes.

There it was, an apology carved into the back of a picture frame and left in plain view.

“It’s extremely baffling,” said Pughes. “You don’t get a note left at a crime scene very often.”

Carolyn Montgomery had a roommate at the time. She worked as a cocktail waitress at the same country club.

She wasn’t home the night of the murder.

“That note would lead you to believe the roommate was the intended target,” said Pughes. “But those leads didn’t pan out.”

Police looked at more than a dozen suspects, analyzed fingerprints, blood and both murder weapons. But forensic technology wasn’t available in the 1970s.

Much of the evidence has since been contaminated.

There was even a question of whether the note was intentionally planted to throw police off.

And so 41 years after her brutal murder, Carolyn Montgomery’s fate is sealed within a cold case.

“She lived until she was 28, that’s it,” said Dequin. “So whoever is out there that did this, they had a full life.”

Dequin Montgomery still wants justice for his mom. The six-year-old boy who lost his innocence that day wants answers.

Or, as he put it: “Closure. For it to be solved. It’s a mystery.”

There is a new reward in Montgomery’s case. Crime Stoppers is offering up to $5,000 for information leading to an arrest or indictment.

“What did she do to deserve this? Montgomery asks.

“Sounds like a monster, for sure.”