Authorities were looking for a 300-to-350-pound shirtless man seen in a video attacking the woman at the gas station.
The attack appears to be random and without provocation, and left the woman, a 25-year-old single mother, hospitalized with serious injuries.
The suspect, who has not been immediately identified, was taken into custody around 7:30 p.m. after a family member turned him in. The family member expressed concern he would hurt someone else or himself.
Investigators say the suspect, who is in his late 40s, is currently on parole for assault.
The assault happened Sunday, May 30 around 7:10 p.m. at a station in the 500 block of Rosecrans Avenue in Gardena.
On surveillance video, the woman is seen pumping gas at her car as the suspect emerges from his black Ford Expedition at the next pump and calmly walks up to her.
He immediately starts punching her repeatedly in the head and body, even as she falls to the ground. As she lays helpless on the ground, he continues punching her again and again. He also grabs her hair to slam her head against the car and the ground multiple times.
The attack continued for at least 40 seconds until he stopped and stood over her motionless body.
Full video: Man attacks woman at Gardena gas station
At that point, three men are seen walking up to the suspect and intervening.
It's not clear if they saw the actual attack from their angle on the other side of the victim's car.
One of the men walks the suspect away and back to his Expedition. At that point the video released by authorities ends. It appears the suspect left the scene as investigators continued to look for him.
Later Friday, authorities said they learned of a second attack apparently by the same suspect the night before.
A 63-year-old woman was attacked Saturday night near the same intersection. She was sitting in her car at a traffic light when the suspect walked up and punched her.
Police believe there may have been other assaults and they are asking victims and witnesses to come forward.
The woman in the gas station attack told Los Angeles County Sheriff's deputies she did not recognize the man and that he didn't take any personal property from her.
She was described as a 25-year-old single mother who was stopping for gas as she headed home from work that day. Detectives say she didn't even notice the suspect until he was attacking her.
"He walked around, she didn't see him," LASD Det. Keegan McInnis told Eyewitness News. "By the time she looked up he had thrown the first punch. You see in the video the attack is pretty vicious. Then he calmly walks away as if nothing had happened."
She suffered severe injuries to her face and head from the attack and was transported to a hospital. She was later released and was recuperating at home.
"This is a 25-year-old single mother who just got off work and was on her way home," McInnis said. "This could be your daughter, this could be your sister, your mom. She was just innocently pumping gas."
"Any info that could help us identify this gentleman and bring him into custody would help your community be safer and help our victim sleep better at night."
"She's afraid to even take her daughter to school right now because of this attack."
The suspect is described as a 35-45-year-old Black man, weighing at least 300-350 pounds, standing about 6 feet to 6 feet 3 inches. He was driving an older model Ford Expedition with matte black paint and black rims. Authorities have not located the vehicle.
McInnis says tips from the public indicate the suspect may live in the area and possibly suffers from mental illness.
They wanted to catch him before he hurt someone else.
"We've seen what kind of terrible things he's capable of."
A flyer with photos of the suspect and more information is available here.
Anyone with information was asked to call Detective McInnis at (323)568-4800. Tipsters can also call Crime Stoppers at 800-222-8477.