A U.S. State Department law enforcement agent from the mainland was arrested early Saturday on suspicion of fatally shooting a Windward Oahu man at the Kuhio Avenue McDonald’s in Waikiki.

Honolulu police identified the alleged shooter as Christopher W. Deedy, 27, and sources who asked to remain anonymous confirmed that he is a federal agent who was off-duty at the time of the incident. The victim was identified by family and friends as Kailua resident Kollin K. Elderts, 23, a Kalaheo High School graduate.

State Department officials refused to confirm that Deedy was here in connection with the Asia-Pacific Economic Cooperation conference that begins Tuesday. His LinkedIn web page identifies him as a special agent working in the Washington, D.C., area for the department’s Bureau of Diplomatic Security. According to the department’s website, the bureau is responsible for providing a safe and secure environment for the conduct of U.S. foreign policy.

Reached in Washington Saturday night, a State Department spokeswoman said only, "We are aware of the incident and we cannot comment on an ongoing investigation."

The incident marks an inauspicious start for what Hawaii leaders had been hoping will be a boom week for the state and Waikiki, where many of the key APEC events are being held. President Barack Obama and the leaders of 20 other Asian-Pacific nations are attending, along with an estimated 20,000 others.

Police said the shooting happened in front of the McDonald’s restaurant at 2237 Kuhio Ave. between Royal Hawaiian and Seaside avenues just before 3 a.m.

Deedy was identified and arrested a short distance away at 2234 Kuhio Ave. at 3 a.m. He was being held Saturday pending a second-degree murder charge, according to police.

Police said initial indications are that Deedy and Elderts did not know each other.

Police said four males got into a confrontation and the victim suffered a single gunshot wound. Paramedics took him to the Queen’s Medical Center, where he was pronounced dead.

Deedy had not been charged as of Saturday night and was at the main police cell block on South Beretania Street.

His LinkedIn page says he is a graduate of Tulane University in New Orleans who worked as an economist with the U.S. Bureau of Labor Statistics before joining the State Department in June 2009. The page also describes him as an agent with the Diplomatic Security Service, part of the State Department’s Bureau of Diplomatic Security.

The bureau, on its website, says DSS agents conduct fraud investigations involving passports, visas and other travel documents.

In an interview online as an alumnus of the Fund for American Studies, Deedy described himself as a special agent assigned to the Washington field office, with two primary duties: criminal investigations and working on personal protection details.

"A typical day in the first capacity varies and could entail performing records checks, conducting surveillance, executing an arrest warrant, or a number of other activities," Deedy said in the interview, posted Oct. 11, 2010. "Working a protection detail varies as well, and could range from liaison activities with visiting foreign delegations to escorting foreign dignitaries throughout the city in a secure motorcade."

YELLOW CRIME TAPE blocked off the entrance to the normally crowded McDonald’s, which is usually open 24 hours a day and is one of the few places late-night visitors to Waikiki can have a cheap bite before going home after a night of partying. Signs on the front doors said it would reopen for business today.

Keo Evans, a bartender at Lojax at Kuhio and Seaside, said he was just leaving work when he heard two or three shots, and then screaming, coming from the McDonald’s.

A man wearing a collared shirt ran from the restaurant, heading in the Ewa direction, Evans said. Inside McDonald’s, Evans said, a man was holding on to the victim, trying to keep him from collapsing.

"There was already a big crowd of people out there (in front of McDonald’s)," Evans said, noting that was unusual. Usually the early-morning action in the neighborhood occurs one block Diamond Head in front of the Waikiki Trade Center, notorious for fights after bars and discos in the building close, he said.

Chuck Crowell, who is renting a unit at the Royal Kuhio vacation condominium across from the McDonald’s, said he was lying down in his room when he heard, "Pow! Pow! Then a pause. Then pow again."

Robert Hackney, owner of the Tiki Tattoo shop next to McDonald’s, said he was shocked to learn there was a killing next door.

"We’ve never had any trouble at all on our block," Hackney said. "The other block down is where you have fights and stuff."

Outside Elderts’ Kuaaina Way house Saturday night, about two dozen young men gathered to remember their fallen friend. Stunned and angry, they stood in the front yard and exchanged what scant information they had about the incident over beers and blasting reggae.

"The (expletive) haole wen’ kill Kollin," said one young man who declined to identify himself. "That’s what happened."

"The family is really hurting right now," one friend said. "Everybody is hurting."

The assembled friends and family declined further comment.

Across the street, neighbor Darlene Fangon, a lifelong resident of Kuaaina Way, recalled how she and Elderts exchanged greetings each morning as they left for work.

"He was a good kid," Fangon said. "The whole family was really friendly. They never bothered anybody."

Fangon said Elderts’ parents recently moved to Hawaii island and that Elderts remained at the house with a brother.

"It’s so unfortunate, so sad," Fangon said. "I had tears in my eyes when my mother told me about it."

Shane Harada, a neighbor who graduated from Kalaheo High School a few years before Elderts, described Elderts as a "nice guy" and said he couldn’t imagine Elderts being involved in such a tragic situation.

"It’s messed up," Harada said. "I would never have imagined something like this."

Star-Advertiser reporters Craig Gima and Rob Shikina also contributed to this report.