Police were continuing their investigation into the Saturday death of a 4-year-old boy who somehow got into the trunk of a car outside his Iroquois Point home and was found there after a frantic search by his family.

The city medical examiner's office said yesterday that autopsy results for the boy — who was identified as Brayden Mara-Villegas — were inconclusive. A cause of death was deferred pending further study and test results, the office said.

Police declined to discuss details of their investigation yesterday.

Brayden was found in the trunk of a car on Ibis Avenue about 2 p.m. Police said the boy's mother was inside cleaning when she couldn't find the boy. A relative went out to search the area, driving a 1993 sedan, and pulled over at one point when he saw a warning light on. When he opened the trunk, he found the boy inside unconscious, a police spokesman said.

Firefighters said the boy had been in the trunk for up to an hour.

Experts said temperatures in the trunk could have exceeded 130 degrees.

The boy was taken to Hawai'i Medical Center West, where he died.

The boy's family declined comment yesterday. Neighbors of the family said the community is devastated.

"The neighborhood is shocked," said Ellie Marcus, who lives down the street from the family.

It's still unclear how the boy got into the trunk.

Police would not say whether the vehicle had folding seats that allowed access to the trunk.

Janette Fennell, founder and president of Kids and Cars, a national organization that raises awareness about the dangers of leaving children unattended in and around vehicles, said a 4-year-old could probably figure out how to pop the trunk open using the lever near the steering wheel. "They watch everything we do," Fennell said.

She added that the 1993 vehicle probably didn't have a safety latch in the trunk to open it from the inside.

All cars built after 2002 are required to have safety latches inside the trunk.

Fennell said that two of the 42 children who died last year from vehicular hyperthermia in the United States were trapped in trunks. So far this year, 20 children have died from vehicular hyperthermia. Two of those children were trapped in trunks.

She said that she knows of no other case of a child in the Islands dying after being stuck in a trunk.

From 1997 to 2007, four children in Hawai'i died of vehicular hyperthermia.

All of those children were left unattended in hot vehicles.