San Francisco 49’ers quarterback Colin Kaepernick is now wearing socks featuring pictures of white pigs as police officers to football practice, as part of his ongoing protest against the police.

Kaepernick upset many NFL fans after he refused to stand for the national anthem at a preseason football game, declaring he was doing so to stand up for black victims of police shootings.

Colin Kaepernick sporting his anti-police socks since August 10th at training camp. #NationalAnthem pic.twitter.com/scobHPXCDK — Robb Ware (@robbware) August 29, 2016

“There’s people being murdered unjustly and not being held accountable,” Kaepernick told the media on Sunday. “People are being given paid leave for killing people. That’s not right. That’s not right by anyone’s standards.”

Kaepernick’s birth mother Heidi Russo criticized the quarterback, accusing him of bringing shame to the family.

“There’s ways to make change without disrespecting and bringing shame to the very country and family who afforded you so many blessings,” she wrote on Twitter.

@Kaepernick7 There's ways to make change w/o disrespecting & bringing shame to the very country & family who afforded you so many blessings. — Heidi Russo (@Heidirn1) August 27, 2016

In July, Kaepernick shared his thoughts on Instagram after two black Americans were shot by police officers.

“This is what lynchings look like in 2016!” he said. “Another murder in the streets because the color of a man’s skin, at the hands of the people who they say will protect us.

“We are under attack!” he wrote a day later. “It’s clear as day! Less than 24 hrs later another body in the street!”