Alapeti Siuanu Tunoa Jr., who was arrested at 6:08 p.m. on the 45-200 block of Likeke Place in Kane'ohe and booked at 7:05 p.m., allegedly beat 30-year-old Janel Tupuola at 5:30 p.m. on Maluniu Avenue in Kailua. Tupuola died at Castle Medical Center at about 6 p.m.

Honolulu medical examiner autopsy findings listed cause of death for Tupuola as "craniocerebral injury due to assaultive blunt force trauma to the head" and manner as homicide.

Eyewitnesses told police Tupuola was clubbed with the butt of a shotgun by the 6-foot-2, 340-pound Tunoa, who was holding the gun by the barrel and swinging it down like an axe.

Police today were seeking a warrant to search Tunoa's Ford Explorer for the shotgun.

In addition to second-degree murder, Tunoa was booked for first-degree terroristic threatening and second-degree assault for alleged offenses against a 69-year-old man who tried to help Tupuola. The man was struck in the head with the shotgun and was treated for injuries at Castle.

Police said that Tupuola had gone to pick up a child at her babysitter's Maluniu Avenue home but saw Tunoa waiting. She fled in her white car before picking up the child and Tunoa gave chase in his Ford Explorer, eventually ramming the woman's car, which caused it to spin around.

Tunoa then allegedly pulled the woman out of her car and started beating her.