Honolulu police have launched an investigation into the death of a 28-year-old man in Kaneohe.

A patrol officer responded to a report of an argument at Ka Hanahou Circle at about 9 a.m. Wednesday.

When they arrived, officers observed the man arguing with a 43-year-old bystander and lying in a truck that did not belong to him.

“The male was combative and punching and kicking the truck’s interior before he slid out of the vehicle and began struggling with the officer and the bystander,” said police spokeswoman Michelle Yu in a statement. “A second officer arrived and the male was handcuffed. The male continued to struggle, and a third officer placed leg shackles on the male and called for an ambulance.”

The man was seated on the ground and leaning against one of the vehicles when he became unresponsive. Officers and the bystander administered first aid until paramedics arrived and continued treatment, Yu said.

The man was pronounced dead at the scene. The Honolulu Medical Examiner’s Office has yet to release the man’s name.

Police have initiated an unattended death investigation.

In addition to the investigation, police have launched an administrative investigation — as is standard procedure — involving the three officers. The officers have 7, 8 and 29 years of service, respectively, with the police department.