When the father of a school shooting victim held out his hand to Donald Trump’s nominee for the supreme court on Tuesday, Judge Brett Kavanaugh looked at him, then turned without saying a word and walked out.

“I put out my hand and I said: ‘My name is Fred Guttenberg, father of Jaime Guttenberg, who was murdered in Parkland,’ and he walked away,” Guttenberg said in an interview with the Guardian.

The moment was captured in dramatic photographs, as well as on video from several different angles. In a statement after the incident, a White House spokesman said that “an unidentified individual” had approached Kavanaugh as he was preparing to leave for the confirmation hearing’s lunch break and that “before the Judge was able to shake his hand, security had intervened”.

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“If you watch the video, you see that’s not the case, ” Guttenberg said. “What the White House said was not true.”

Kavanaugh made eye contact with him “long enough for me to say who I was”, Guttenberg said. “He could have absolutely shook my hand and said: ‘I’m sorry for your loss.’ I mean – if nothing else.”

In an email, the White House spokesman, Raj Shah, wrote: “I stand by my tweet/email on this topic,” when asked about video of the interaction that appears to contradict the White House’s claim that security had intervened “before the Judge was able to shake [Guttenberg’s] hand”.

Kavanaugh, a champion of gun rights, has been backed by the National Rifle Association, which announced in August that it was spending at least $1m on a national advertising campaign to support the judge’s confirmation to the supreme court.

In the video advertisement released by the NRA, an announcer warns, “Four liberal justices oppose your right to self-defense. Four justices support your right to self-defense. President Trump chose Brett Kavanaugh to break the tie. Your right to self-defense depends on this vote.”

An NRA spokeswoman did not respond to a request for comment on the interaction between Kavanaugh and the father of a school shooting victim.

Guttenberg has become a prominent advocate for gun control, including stricter regulation on military-style “assault weapons”, after his 14-year-old daughter, Jaime, was shot to death in her school hallway this February with a legally purchased AR-15-style rifle. He said he had attended the hearing in hopes of making Kavanaugh consider the consequences of his position on the second amendment.

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“I wanted to be there to make sure he understands what he’s being asked to do has real-world consequences,” Guttenberg said. “As he sat there thinking about his beautiful family, I wanted him to know that my family was torn apart by gun violence, preventable gun violence, the kind of gun violence that people can do something about, and he doesn’t believe that.”

Kavanaugh wrote in a 2011 dissent that the District of Columbia’s assault weapon ban was unconstitutional, because the weapons were already “in common use”. He argued that there was no “meaningful or persuasive” distinction between semi-automatic handguns and rifles, and noted, correctly, that handguns were more frequently used in crime than rifles are.

Gun control advocates say that if Kavanaugh is confirmed to the supreme court, which is currently divided between justices who support gun rights and gun control, he may serve as the swing vote to make state and federal assault weapon bans unconstitutional, as well as to tear down local restrictions on carrying guns in public.

Earlier in the day, Guttenberg said, he had been publicly introduced during the hearing by Senator Dianne Feinstein, who had invited him as her guest. He said he thought Kavanaugh would probably have been able to recognize who he was from that introduction, even before he introduced himself again.

Asked if he thought the NRA’s backing of his confirmation might have played any role in Kavanaugh’s choice not to speak to him or shake his hand, Guttenberg said: “You know what? I don’t know. I don’t put myself in other people’s heads.”

After lunch, when the hearing resumed, “security came and took me out of the room and they kept me out for 15 minutes, questioning me”, Guttenberg said. “They took my license and wanted to know why I was there.”

Afterwards, he said, he was allowed to return as the hearing continued.

Guttenberg added in an interview with CNN on Tuesday evening that he thought security took him out of the room after the break because Kavanaugh pointed him out to them and asked them to.

Gun control advocates, including some student survivors of the Parkland shooting, argued on Tuesday that Kavanaugh’s refusal to greet the father of a gun murder victim showed a lack of character, as well as reflecting his strongly pro-gun legal views.

Andrew Pollack, another, more conservative father of a Parkland gun violence victim, publicly defended the judge on Tuesday. “Judge Kavanaugh was not responsible for the Parkland school shooting that killed my daughter,” he said, placing blame instead on local law enforcement and school officials. “Judge Kavanaugh is a decent man and should be confirmed. Stop weaponizing Parkland to advance a dangerous political agenda!”