A Federal Way man is facing first-degree manslaughter charges after he allegedly slapped a Korean Airline manager, who died when he hit his head on concrete from the blow on July 6.

Taumailelei Mapusua Jr., 27, is being held on $1 million bail because he is considered a flight risk due to having family in Nevada and Samoa.

“This was a self-admitted, unprovoked assault on a coworker that resulted in death,” a prosecuting attorney said in the charging documents.

Victim Jason Keum and Mapusua got into an altercation at SeaTac Airport on July 5. The two apparently disagreed about which piece of equipment to use to stabilize a cargo plane. Keum was the manager of Korean Airline and the suspect is a cargo handler employed by Integrated Airplane Services, the company Korean Airline uses to load and unload large body cargo airplanes.

Post-Miranda, Mapusua told police he slapped Keum on the side of the face, which caused him to fall backwards and hit his head on reinforced concrete tarmac, a material used for surfacing roads consisting of crushed rock mixed with tar.

Keum lost consciousness and experienced a cracked skull and internal brain bleeding, which the medical examiner determined as his cause of death.

Port of Seattle Fire Medics transported Keum to Harborview Medical Center for brain surgery but he died the next day.

When they arrived on scene, they found the victim lying on the tarmac being assisted by a coworker.

“His breathing was labored and blood was coming out of his mouth,” the charging documents state.

Mapusua’s coworkers told the fire department captain what happened and police officers soon interviewed Mapusua in a break room.

He told the officers “it was my fault,” the documents continue. At the police station he later told a detective, after his Miranda Rights were read, that he lost his temper and slapped Keum with an open hand.

“He didn’t know he was seriously hurt until he saw blood coming out of his mouth,” court documents state.

A few days later, an autopsy revealed Keum had bruising to the left side of his face, a cut on the inside of his mouth on his left cheek, a fractured skull and internal bleeding on the back of his head.

Mapusua cannot have contact with Keum’s family or any employees at Korean Airline or Integrated Airline Services.

His arraignment is set for July 23 at King County Superior Court.