In a campaign video, Joe Biden claims he met with all families affected by the 2012 Sandy Hook school shooting in Connecticut.

But at least one family member who lost a loved one in the bloody massacre – in which a gunman killed 20 children and six adults – claims Biden is distorting the facts.

"The issue of gun violence has been a concern of mine for a long, long time," Biden says in the video. "What really got to me though, really firsthand, was what happened up at Sandy Hook.

"I think I met with every one of the parents," he continues, "and ... the families of those who were lost."

But JT Lewis, 19, whose brother Jesse, 6, was killed in the attack, which happened just 11 days before Christmas, says former President Obama met with each of the grieving families after the Newtown shooting — not Biden.

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“This is a lie,” Lewis writes in a Twitter message about Biden’s claim. “Obama came to Sandy Hook and met with every family. Joe Biden DID NOT.

“In fact,” Lewis adds, “my family was not allowed on Air Force One because we refused to support Obama/Biden gun control efforts.”

Biden addressed Sandy Hook family members June 15, 2016, CBS News reported, but it was unclear whether all families were represented.

In another post, Lewis reminds his followers of another instance in which Biden got his facts wrong regarding a school shooting.

He refers to an incident from August of this year, when Biden claimed to have been vice president at the time of the Marjory Stoneman Douglas High School shooting in Parkland, Fla., that left 17 people dead.

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But the Parkland shooting happened in February 2018, more than a year after Biden had left the vice presidency.

“@JoeBiden is either a liar or he’s losing his mind,” Lewis concludes.

Gaffes have been one area of concern for the Biden campaign, which has been losing momentum in recent weeks. Other topics that have some supporters worried include increased scrutiny of Ukraine business dealings that involved Biden’s son, Hunter Biden.

A recent poll in the early primary state of South Carolina shows both Sen. Elizabeth Warren and Sen. Bernie Sanders gaining support in the Palmetto State since July, while Biden has lost support over the same period.