A Federal Way man pleaded not guilty on Wednesday to 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 still being held on $1 million bail because he is considered a flight risk due to having family in Nevada and Samoa.

Mapusua allegedly got into an argument with victim Jason Keum at the 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 was 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.

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.

According to charging documents, Mapusua told the officers in the investigation, “It was my fault,” and that he had lost his temper but didn’t know Keum was seriously hurt until he saw the blood coming out of his mouth.

Mapusua’s case setting hearing is set for Aug. 13.