Andrew Nakoa Jr. was buying beer at a Kalihi market in the fall of 2004 when a fight broke out between his friend and a group of men hanging out near the store's entrance.

During the melee, Nakoa, 21, was stabbed once through the shoulder in front of Fuji Market in the 500 block of North King Street and died. Police identified the killer, but the 17-year-old boy fled to Micronesia. The state cannot extradite juveniles from the island nation.

Of the 111 homicides in Hono-lulu since 2001, the death of Nakoa is one of a thirteen that officially remain unsolved. As in many of these cases, law enforcement agents know who the killer is, or at least have an idea, but are restrained by a variety of factors from making an arrest.

But whatever the reason, the lack of closure means those who have lost a loved one cannot let their pain go.

"Our holidays are not the same. My family, my parents, my brothers, my cousins they still asking, 'What, they never catch the guy yet?' " said Andrew Nakoa Sr. "Me and my wife, we grieve. What can we do? We had plans for Junior. He had a job interview day after he died. This guy stopped the dream. He killed the dream."

More than 80 percent of the 1,264 homicides investigated by Honolulu police from 1970 through last year have been resolved, a rate that is considered successful compared to comparable jurisdictions on the Mainland.

Of the 208 murders that remain unsolved, homicide Lt. William Kato says often investigators identified a suspect but were unable to get a crucial piece of evidence tying the suspect to the crime.

"Witnesses a lot of times move away or die. Family members die, suspects die, those are some of the bigger issues," said Kato. "You look at a case, you think you might be able to work the case, but when you try to trace back and talk to witnesses you find out many have passed or moved away and now you really don't have that place where you can go. And naturally, people forget."

The most recent unsolved homicide perplexing police is the fatal shooting of a 31-year-old Punahou man.

Investigators have interviewed more than a dozen witnesses in connection with the March 10 shooting.

Jason Nam, a delivery truck driver for the Govinda's Fresh Juices company and a bodybuilder, was hit with a baseball bat and then shot in the neck while cleaning his car. More than 12 hours of interviews with friends and relatives have not helped police find a motive, or the identities of three men who allegedly beat and shot Nam to death, police said.

As brutal and heinous as a murder may be, the killer often doesn't leave any evidence or flees the jurisdiction soon after the crime. Old evidence gets lost or tainted by time and the elements. Witnesses disappear or their memories fade.

In Honolulu, two separate groups of five law officers, three with the police department and two from the state attorney general's office, are dedicated to finding the killers.

Officials on both sides say they cooperate and assist one another, and the attorney general's unit is staffed with retired police homicide detectives.

SEARCH FOR EVIDENCE

As difficult as it can be to locate witnesses, finding evidence and case files from murders before 1980 can be next to impossible.

HPD keeps evidence stored in several different warehouses on O'ahu, and locating and pulling files is a time-consuming process. Police must submit a request to the records division, which then has to search the warehouses for the file. Saying the search is akin to finding a needle in a haystack is not that far from the truth, police said.

"When headquarters moved from Beretania Street to Alapai Street, a bunch of evidence was stored in different warehouses," Kato said. "We have to find it, and who knows the condition. From 1990 (the evidence) is a little more consistent and a little easier to find. Plus a lot of the detectives around at the time are in the community and we can call and ask questions. Institutional memory evaporates (after a while)."

Further complicating the situation is that older physical evidence, like blood-stained clothing, was stored for years in humid containers without air conditioning, he said.

DNA evidence does not keep well without climate control, and evidence from before the use of DNA technology by law enforcement is "probably gone," police said.

Since assuming control of the department, Police Chief Boisse Correa has purchased several refrigerated storage containers for new and old evidence that is deemed salvageable, Kato said. All new DNA evidence is uploaded into a national database, the Combined DNA Index System, run by the U.S. Department of Justice.

Detectives run all DNA evidence collected from homicide scenes through CODIS and the Justice Department's national Sex Offender Registry.

"There are maybe four cases where we've been seriously sending DNA samples off to the different (Mainland) labs hoping to get a hit," Kato said, including a case from 2000, another from the "early 90s" and two more from the 1970s. Kato declined to discuss specifics.

"That's the thing — a lot of these cases, it's not a matter of 'we have no idea.' We've narrowed it down, we're pretty sure we know who did it, but we just need that last piece of evidence to push it over to the prosecutors."

STATE INVESTIGATORS

In addition to HPD's cold case efforts, the unit of investigators with the state attorney general's office also handles unsolved murders.

Made up of two retired HPD homicide detectives, the unit is handling 16 cold cases from all four counties, said Donald Wong, chief investigator for the attorney general's office.

Where HPD can only investigate deaths on O'ahu, the attorney general's unit can move freely among the counties.

The group is backed by the Naval Criminal Intelligence Service.

"The good thing about this is you have a couple of extra eyes and pairs of hands," Wong said. "These are not easy cases but if we can resolve a couple it's a win-win for everybody. A cooperative, collaborative effort is what we're looking for because in the end it is the victims' families that win. If we get lucky we can bring some closure."

Reach Peter Boylan at pboylan@honoluluadvertiser.com.