A 44‑year‑old Santa Rosa homeless woman suffered life‑threatening injuries Sunday after being struck repeatedly in the head with a hammer before police caught her attacker and found her unconscious in his SUV, according to Santa Rosa police.

Officers arrested Robert Holladay, 55, a Santa Rosa homeless man, suspecting him of attempted homicide and kidnapping, police Sgt. Josh Ludtke said Monday.

The woman, who was not identified, was beaten beyond recognition. She is being treated at Santa Rosa Memorial Hospital.

Detectives Monday learned the two knew each other but it remained unclear if they had any kind of relationship and the investigation into their backgrounds continued, Ludtke said. The motive also remained unclear.

Detectives weren’t able to find witnesses to what led to the assault, which occurred about 8:50 p.m. Sunday on a Montgomery Drive sidewalk and in the road at Second Street near downtown Santa Rosa.

“It was crazy. I could hear like a woman screaming,” said Ari Elegante-Newman of Santa Rosa, who was driving by and called 911. “I see this guy dragging this woman down the sidewalk. I thought, ‘Is this really happening?’”

He said he saw the suspect throw the woman into the vehicle and then “I saw him hit her at least five, six times. I saw the arm swinging.”

The suspect headed east and officers caught up to the older model, faded red, crossover SUV on Fourth Street at Farmers Lane. The man pulled over for the patrol car, got out and addressed officers.

There was a significant amount of blood on his hands and clothing, Ludtke said.

“He gets out, says ‘Hey what’s going on?’ Nonchalant about being stopped,” Ludtke said. “When asked if he was alone, he said ‘Yeah.’”

Officers looked into the vehicle. “She’s crumpled up on the floorboard, bleeding to death,” Ludtke said.

Police found a bloody hammer, which they suspected was the assault weapon, inside the SUV.

Holladay and the woman had been staying in their vehicles, most likely parked close to each other where the attack occurred. Holladay had been living in Napa prior to Santa Rosa, where he was living in his vehicle. The woman had been living in her Nissan sedan and had been in the Santa Rosa area for some time, the sergeant said.

Both vehicles were towed for evidence.

Holladay has a history of minor crimes. He was being held in the Sonoma County Jail Monday in lieu of $1 million bail.

The hammer assault was the latest incidence of violence in Santa Rosa involving a homeless person.

Since April there have been at least two stabbings, two car pursuits — one involving a stolen car — and a carjacking. In 2016 there were at least three homicides in the city involving homeless suspects and victims, according to police.

Ludtke said the majority of violent crime in the city used to involve gang-related suspects but now involves the homeless.

He asked anyone with information to contact detectives at 707‑543‑3590.

You can reach Staff Writer Randi Rossmann at 707‑521-5412 or randi.rossmann@pressdemocrat.com.