(CNN) -- Tears glistened on the black and purple bruises covering 91-year-old Rodolfo Rodriguez's face as he described being attacked by a group of people while going for a walk on the Fourth of July.
"I can't walk anymore," Rodriguez said in Spanish. "I'm in so much pain."
He'll be turning 92 in September, Rodriguez said, and he's never been hurt like this before, in a life working the fields with cattle and corn.
He had traveled from Michoacan, Mexico, to visit his family in Willowbrook, California, a city in Los Angeles County, his grandson Erik Mendoza said.
He makes the trip about twice a year, and takes a walk through the neighborhood every day after lunch, Mendoza said. "Everyone in the neighborhood knows him already," he said.
Rodriguez said he was walking to a nearby park on Wednesday when he passed a woman and a little girl. Without warning, the woman assaulted him, he said, hitting him with a concrete block and enlisting a group of men to join in beating him.
"I didn't even bump into her kid," Rodriguez said. "I just passed her and she pushed me and she hit me until she was done."
Police are looking for "a female suspect and three to four male suspects" in the assault, the LA County Sheriff's Department said in a statement Monday night.
Authorities don't know at this time if any weapons were used or what the motive might have been, the statement said.
"We are concerned, especially with the type of crime they committed," Sheriff's Deputy D'Angelo Robinson told CNN affiliate KTLA . "There was what appears to be a 4-year-old child there who witnessed the entire thing. We can't have these kind of people like that out in the streets."
Misbel Borjas was driving by when she saw the woman hitting Rodriguez repeatedly in the head with a concrete block, she said.
"I heard her saying, go back to your country, go back to Mexico," she told CNN by phone. "When I tried to videotape her with my cellphone, she threw that same concrete block, tried to hit my car."
Rodriguez said he doesn't remember when the woman picked up the concrete block, but he remembers being hit repeatedly. At one point, he says, the woman ran up to a group of men nearby and told them Rodriguez was trying to take her daughter away from her -- so the men joined her and started kicking him as he lay bleeding on the sidewalk, Rodriguez said.
"But that's not true," he said, through tears. "In the years I have been alive I have never offended anyone."
Mendoza said his grandfather suffered a broken jaw, broken cheekbones, two broken ribs and bruises on his face, back and abdomen. He spent five or six hours in the hospital, he said.
The family has started a GoFundMe campaign to help cover Rodriguez's medical costs.
As his grandfather laid back in a reclining chair at the family home, wearing a white T-shirt and blue plaid pajamas, Mendoza kissed him on one of the few places he hadn't been injured: the top of his head.
"We think we have an idea (on who the suspects are) but I just want police to find them," Mendoza said. "That's all our family wants, justice for our grandpa."
™ & © 2018 Cable News Network, Inc., a Time Warner Company. All rights reserved.