SAN FRANCISCO (CBS SF) – Thanh Nguyen just couldn’t remain silent. He needed to voice his outrage over the brutal attack of his elderly mother in broad daylight in San Francisco’s Tenderloin District — an assault left her badly bruised and battered.

Nguyen is struggling to understand the motive behind the attack since his mother was not robbed in the incident.

“Hearing all the other stories about what is happening around San Francisco and other people who are (so) afraid that they don’t speak up or couldn’t post pictures about what happened to them, I wanted to show people that this is real,” he said. “My mom wasn’t even robbed so that kinda was like unsettling. You just attack someone.”

Nguyen posted photos to his instragram account and a description of what happened.

“My brother was carrying groceries and heard two thuds and saw my mom unconscious on the floor, my brother saw the guy run down Market and chased him down the block towards Market street,” he posted. “The guy tried hopping onto the K train on Market to escape, but my brother chased him off the train and down Market street towards Embarcadero. As they were running this scum ran into a group of guys just hanging at the corner; and when he approached one of the guys sucker punched him almost knocking him out. He was able to pull himself together and run back to my mom.”

His mother spent several days in the hospital before she was released and allowed to return home.

On Monday, San Francisco polices said they had arrested 34-year-old Michael Turner for allegedly assaulting two elderly women in the Tenderloin including Nguyen’s mother.

Turner faces multiple charges, including aggravated assault, battery, two counts of elder abuse, along with violating probation. Police said Turner has also been charged with violating an order to stay away from Market and Jones streets due to a prior weapons offense.

He is being held without bail, according to jail records.

Anyone with additional information about the case is asked to contact the department’s tip line at 415-575-444 or texting “TIP411,” with “SFPD” at the start of the message. Tips