Six months ago, a young man with a love for playing the guitar and helping people was murdered.

It is only a matter of time until Andrew Graham’s killer is brought to justice. It has to be.

His family deserves something resembling closure. Can justice help ease the pain?

“I don’t know how I’m going to feel,” Graham’s mother, Cyndi Gelston, said on a recent rainy morning. “Nothing is going to bring my son back. He was a good man with such potential. They robbed the world of that.”

When Graham was found dead in November, Centennial had not seen a homicide investigation in three years.

The types of crime you generally hear about in the south suburbs are incidents like theft or mischief of some sort. People leaving their car doors unlocked and having their sunglasses stolen. Kids spray painting a stop sign.

You couldn’t see this coming.

There have been media reports linking the murder to gang members from Denver who followed Graham to Centennial on the light rail. That has not been confirmed by authorities, though.

“We’ve had media coverage lately that was the result of information obtained inappropriately,” Arapahoe County Sheriff Grayson Robinson told me April 29.

Graham was 23 when he was found shot to death in the early morning hours of Nov. 6. Details from police reports and his mother paint a picture of what should have been a routine night for a young man with big things ahead of him.

The recent University of Colorado graduate had been making his way home via public transportation from Boulder, where he was to attend grad school in January. He had signed a lease on an apartment up there and was set to study computational engineering.

Graham’s mother said at one point that night, her son had stopped at Union Station in downtown Denver to bring food to some homeless men. He was prone to random acts of kindness.

A surveillance video showed Graham getting off a light rail train at 11:40 p.m. Nov. 5 at the County Line and I-25 station.

The mystery lies in what happened next. Graham was headed on foot to his parents’ Centennial home a few miles away. A member of the university’s Ultimate Frisbee team, Graham was active and walked everywhere he could, his mother said.

His body was found at 5:30 a.m. in the 8700 block of East Phillips Place, about six blocks from his family’s home.

The Willow Creek neighborhood where Graham was killed is like the rest of the city: a place you feel safe. In 2009, for the fifth year in a row, Centennial had the lowest crime rate in the state among larger cities, according to a survey by a Washington, D.C.-based company.

Centennial’s population of about 102,000 ranks in the top 10 in Colorado. But for the most part, it has avoided big-city crime in its 9-year history.

Last fall, there was no reason to believe murder was coming to town, certainly not in the way it did.

A random encounter.

That’s likely what it was, according to the sheriff’s office. Graham’s money, credit cards and cell phone were not stolen.

Suddenly, the sheriff was tasked with something out of the ordinary in his jurisdiction: catching a killer.

That Robinson will not comment on details of the investigation is standard in this type of case.

Law enforcement authorities typically will not release any information they feel could jeopardize an investigation and, ultimately, diminish public safety.

But would the public, particularly the people of Willow Creek, feel safer if they knew more? Or is believing that law enforcement is hot on the trail enough?

Gelston, for one, said she is pleased with the way the investigation is being handled.

“I know that the police are doing everything they can,” she said. “They’re really working very hard in building a case that results in a conviction. I have total faith in them.”

The department has dedicated extensive resources to the case, and the community is safe, Robinson said. He has believed from the start it was a random encounter.

The veteran lawman has gotten to know quite a bit about Graham. So much promise and purpose in that young man.

Robinson won’t have this investigation straying off course.

“My position is, we are going to do this right,” he said. “Right doesn’t always mean quick.”

Six months.

“Sometimes I feel like it’s been forever,” Gelston said, “and sometimes I feel like it was yesterday.”

There can be no happy ending to this story. The only acceptable conclusion is the one in which the killer is caught, convicted and sentenced.

Tonight, a family will do what it can. A mother will light a candle in front of her son’s picture to honor his memory and keep him out of the dark.

Chris Rotar is a news editor for Colorado Community Newspapers.