BUFFALO, N.Y. (WIVB) – The self-proclaimed white supremacist accused of killing 10 people and injuring three others in the Buffalo supermarket mass shooting is expected to plead guilty Monday to the state charges against him, multiple sources confirmed to News 4.

An attorney for accused shooter, Payton Gendron, confirmed the plans for the plea to CBS News.

“There was never any doubt of whether he was guilty or not," said Garnell Whitfield Jr., whose mother, Ruth, was killed in the attack. "I know he will never see the light of day again.”

Monday marked sixth months since the mass shooting. Buffalo held a moment of silence and lit buildings up in orange to signify gun violence prevention.

"Although it’s still been 6 months, mentally it feels like I’m still there every day," the son of a victim told News 4. "So although time physically is going by faster, mentally, it’s still 5/14.”