SAN JOSE (CBS SF) — Matt Mahood, President and CEO of the business advocacy group Silicon Valley Organization (SVO) resigned Thursday in the wake of a racist campaign ad on its website.

It shows an image of a group of Black men on a street in what appears to be a riot in South Africa accompanied by a graphic reading “Do you really want to sign onto this?”

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The campaign ad, which has since been deleted, was part of an attack against San Jose City Council District 6 candidate Jake Tonkel, alleging he supports defunding the police.

After the ad was published, three board members resigned in protest over the image Wednesday and the organization placed Mahood on administrative leave. On Thursday morning at a press conference, SVO Chairman Mike Bangs announced Mahood had resigned.

Later Thurday morning, Mahood issued a statement of apology, saying the organization had “made some mistakes” during his nine-year tenure and that he as CEO took full responsibility.

“I am very sorry for the completely unacceptable image that was put up on our website earlier this week,” Mahood’s statement said in part. “That image and messaging DOES NOT represent who I am as a man, a father, a husband or community leader. The people who know me and work with me on a regular basis know that. And I also know that the image and messaging does NOT represent the values of our members or the SVO Board of Directors.”

SVO Executive Vice President Madison Nguyen announced at Thursday’s press conference that the political action committee for SVO had ceased all activity and the PAC and board members would undergo sensitivity training.

“I am very well aware that the SVO has made several mistakes over the past years that were culturally insensitive and racist. For that, we deeply apologize,” said Nguyen.

SVO board member Kevin Surface urged the board members who resigned to come back and help fix the organization’s problems from within.

“A person who says ‘I am not racist’ is not doing enough. Mark my words. In fact, they are doing nothing. They think they’ve done their duty,” said Surface. “We have to do more to fix it.”

Tonkel said Thursday the entire SVO leadership has to go.

“To be honest, I know that there are lots of people that have been going in and out of this organization that have been very aware for years at the type of misinformation that they perpetuate,” said Tonkel. “I think they need to take a very hard look at restructuring the organization with new leadership in order for us as a community to begin to trust them again.”

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A group of non-profits and charities on Thursday lined up to denounce SVO at another press conference Thursday and announce they were rescinding their membership in the group.

“We are appalled at the blatant racist fear-mongering tactics,” said Gregory Kepferle, CEO of Catholic Charities of Santa Clara County. “We will no longer sit politely and allow the racist tropes, messages and policies of these organizations to continue.”

It wasn’t the SVO’s first controversial ad. Others have darkened the skin tone of Latino candidates.

On Wednesday, Nguyen announced a third-party investigator was hired to determine how and why the image was posted.

“Their investigation will explore all levels of the organization starting with leadership and will include inherent cultural issues in the organization that might have contributed to this disgraceful post, along with recommendations for necessary changes,” said Nguyen.

“Their whole point was to try and scare people with racist undertones and try to stoke that fear within our community. in order to manipulate the outcome of an election,” said Tonkel on Wednesday.

Tonkel’s opponent, SVO-backed incumbent Dev Davis, also denounced the ad and said she had nothing to do with it. Davis noted that she first saw it only after it was published.

“My first reaction was shock and horror at seeing a racist image,” said Davis. “Our country is in a tumultuous time right now and unfortunately the tone from the federal government has seeped into local elections.”

Davis also said she was donating the money she received from the group to the local NAACP.

The SVO did not answer any questions at its news conference, leaving some to wonder how and why such a deeply rooted San Jose organization could turn out material that was so offensive to so many.

“Organizations have a tendency to rear its true head, and raise its true voice, based on what it really believes,” Rev. Ray Montgomery, a Baptist minister and longtime social justice advocate with the group PACT.

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Len Ramirez contributed to this story.