An Oahu grand jury Wednesday indicted a 43-year-old Maili man on one count of second-degree attempted murder in the beating of a 51-year-old Waianae woman with whom he told police he was having an affair.

She is not expected to survive.

The Honolulu Prosecutor’s Office called the attack by Oscar Kanoa “brutal.”

Kanoa is accused of attacking, from late Friday through early Saturday, Bonnie Vierra, with whom he admitted to having an intimate relationship.

Police found firefighters rendering aid to Vierra, who was unresponsive when they arrived at 3:28 a.m. Saturday at 86-142 Leihoku St.

As Emergency Medical Services personnel were loading her into the ambulance, police noticed bruising to both eyes, forehead and cheeks, court documents said.

Kanoa was seen with his left hand swollen and red around his knuckles. Patrol officers documented the incident as an “injured, cared for” case.

A doctor at the hospital found Vierra had multiple facial fractures, bleeding in the skull, resulting in brain herniation, a nonsurvivable injury from blunt injury to the head and face, and multiple external bruises in those areas, police said in court documents.

She remains hospitalized, and Kanoa could be recharged with second-­degree murder, should she die of her injuries, the Hono­lulu Prosecutor’s Office said in a news release Wednesday.

Kanoa told police he was “leaving his wife for Vierra, but when he came over she was texting another guy, was drunk and acting crazy before she had a seizure,” according to court documents establishing probable cause to detain him.

But he later changed his story and told police that she went limp while they were having sex and he called 911.

Kanoa told a third story to police, saying he did not touch her sexually when she told him she felt dizzy. He said he went to the restroom, and returned to find her unresponsive.

In his written statement, Kanoa gave yet another story saying he arrived at her home at 10:30 p.m. and thought she was asleep, so he went to the living room to smoke a “joint.” He said Vierra was dizzy and throwing up.

EMS brought Vierra to The Queen’s Medical Center in critical condition.

An EMS paramedic said Kanoa told her Vierra was drunk, had a seizure and fell, and that her injuries were because they had been wrestling.

Police reclassified the case to first-degree assault.

Police obtained a search warrant and recovered surveillance footage showing Vierra coherent and uninjured at 7:57 p.m.

Then at 8:46 p.m., Kanoa arrived at the front gate while she was doing yardwork. She let him in and the two were talking inside the home.

At 9:03 p.m. they appeared to argue in the garage, and he was seen forcibly pushing her into the house. She tried to open the garage door and flee before it closed, but was instead forced into the house, court documents say.

Police found and arrested Kanoa Sunday on suspicion of second-degree attempted murder.

His bail was set at $1 million, according to a spokesman with the Honolulu Prosecutor’s Office. However, it appears it had been set at $2 million by a district court judge when the initial complaint was filed Tuesday.

Second-degree attempted murder is punishable by a mandatory life sentence with the possibility of parole.

Kanoa has a criminal conviction record that includes driving under the influence of an intoxicant in 2013 and twice in 2011, third-degree assault in 2000, and reckless driving in 2013.

Honolulu Prosecutor Steve Alm said, “Domestic violence is a scourge in our community, and we will hold Kanoa accountable for his alleged violent and dangerous behavior.

“To anyone out there who does not feel safe in a domestic situation, reach out to family and friends for support and visit the Hawai‘i State Coalition Against Domestic Violence at www.hscadv.org or call the Domestic Violence Action Center at (808) 531-3771 to get help,” he continued. “And always call 911 in an emergency.”

“I thank HPD for its good detective work that pieced together the events that led to this tragic incident,” he said.