WASHINGTON — The Democratic presidential contest’s recent focus on gun control has brought with it some raw emotions and sad memories: The slaughter of 20 children and six educators at Sandy Hook Elementary School in 2012.

Sandy Hook was mentioned 11 times in the Democratic debate in Brooklyn earlier this month, and at least five family members of Sandy Hook victims have appeared at events for Hillary Clinton. Among them is Erica Smegielski whose mother was killed in the shooting and who also stars in a TV spot supporting Clinton.

“No one is fighting harder to reform our gun laws than Hillary Clinton,’’ Smegielski says in the spot which is airing in Connecticut. “She is the only candidate who has what it takes to take on the gun lobby. She reminds me of my mother: She isn’t scared of anything.’’

Connecticut is one of five states voting on Tuesday; the others are Rhode Island, Delaware, Maryland, and the biggest prize, Pennsylvania.

The Sandy Hook killings are latest in a string of tragedies that have been replayed this year in a Democratic contest that has delved deeply into issues including police brutality, race relations, and gun control. Family members of black men who have been shot by police in controversial circumstances have voiced support for either Clinton or Bernie Sanders.

Clinton, who often localizes the primary contests, has begun focusing on the school massacre in Newtown, Conn.

Gun activists say the particularly horrific nature of the Sandy Hook killings — so many children killed so quickly — set it apart from other mass shootings because it jolted the country to pay attention to gun control in way that many previously hadn’t.

So for some, the Clinton campaign is providing a fresh national platform to make their case. But for others affected by the shooting seeing and hearing about the Sandy Hook tragedy on the news again is jarring, particularly connected to a presidential campaign.

“It brings things flooding back,’’ said Mitch Bolinsky, a Republican who represents Newtown in the state’s General Assembly.

“This level of attention is something that I believe is not generally something most people in the community want to deal with,’’ Bolinsky added. “There are hundreds of families in Newtown, not all of them want to relive this.’’

He said he shuts off the television when Clinton’s Sandy Hook spots play. But he acknowledged that others believe they have a special burden to speak out because the killings in Connecticut struck such deep chord in the country.

“That is their right,’’ he said. “It’s absolutely their right. It doesn’t mean I want to watch it on the news.’’

Jane Sanders, the wife of Clinton’s Democratic rival, chided Clinton for holding events with Sandy Hook families.

“I just don’t like to see it be politicized,’’ Sanders said on CNN just after the network covered Clinton holding a panel in Hartford that included family members of Sandy Hook victims.

(That comment prompted Smegielski to issue a public invitation to Jane Sanders via Twitter. “Will you be in CT this weekend?’’ Smegielski wrote. “You’re welcome at my house any time. I would love to open dialogue on this issue.’’)

Clinton anticipated this line of objection. During the Hartford forum she applauded the families for speaking up and wanting to change the country’s gun laws.

“When you take a stand against gun violence and against the gun lobby, you are subjected to some of the most vile harassment on the Internet that you can imagine,’’ Clinton said. “It is beyond decency.’’

Indeed, for activists and family members of the victims, Clinton’s embrace of their cause is welcome evidence that their activism is working as intended.

“The Democratic nominees have been batting each other over who would be best to take on the NRA and save lives,’’ said Erika Soto Lamb, a spokeswoman for Everytown for Gun Safety, who works with family members of Sandy Hook victims.

“It is definitely the right time and place for this discussion,’’ she said. “After what happened in Sandy Hook, one of the most horrific mass shootings in America, something has to be done. We feel it is wonderful that this level of discussion is occurring at the presidential level.’’

Last week Clinton held a “Gun Violence Discussion’’ in Hartford with the family members of several Sandy Hook victims, drawing national attention.

“I am here to tell you I will use every single minute of every day, if I am so fortunate enough to be your president, looking for ways that we can save lives, that we can change the gun culture,’’ she said.

For Clinton, focusing on Sandy Hook includes a specific political advantages: The case highlights one of the sharper contrasts between herself and Sanders on gun control.

Clinton wants victims to be able to sue manufacturers when their weapons are used in mass shootings, a step that the Sandy Hook families are now attempting to do. Sanders voted for legislation to shield gun makers from victim lawsuits.

Clinton’s campaign has tracked the Sandy Hook case closely, issuing news releases on legal turns in the case.

Sanders, in an April 1 meeting with editors from the New York Daily News, said he didn’t believe victims of a gun crime should be able to sue the gun manufacturer — although he later acknowledged the right of anyone to bring a legal case.

Clinton’s emphasis on gun control is new. When she ran for president in 2008, she was far less outspoken on the issue.

Then, she stressed her comfort with guns and would frequently talk about shooting for sport.

The talking point prompted Barack Obama, at one point, to observe: “She is running around talking about how this is an insult to sportsman, how she values the Second Amendment.’’

He famously added: “She’s talking like she’s Annie Oakley.’’

Annie Linskey can be reached at annie.linskey@globe.com. Follow her on Twitter @annielinskey.