Erica Garner, shown here at a protest Dec. 11, 2014, died Saturday at age 27 after suffering a massive heart attack a week ago. She became an activist against police brutality after her father, Eric Garner, died after being put into a chokehold by a New York police officer. (Andrew Burton/Getty Images)

Erica Garner, a criminal justice reform activist who died Saturday at age 27, was mourned by progressives whom she had worked with — and some whom she had criticized.

“Erica Garner’s death is a horrible tragedy,” said New York Mayor Bill de Blasio, who sometimes was a target of Garner’s activism, in a Saturday morning tweet. “I am praying for her family, who have already been through so much. This city will miss her unshakable sense of justice and passion for humanity.”

Sen. Bernie Sanders (I-Vt.) in a statement called Garner, who endorsed his 2016 campaign for president, an “exceptional young woman” who died too soon.

“She was a loving daughter, sister, mother, friend — and though she didn’t ask to be an activist, she responded to the personal tragedy of seeing her father die while being arrested in New York City by becoming a leading proponent for criminal justice reform and for an end to police brutality,” said Sanders. “I had the honor of getting to know Erica and I was inspired by the commitment she made working toward a more just world for her children and future generations. She was a fighter for justice and will not be forgotten. Jane and I send our deepest condolences to the entire Garner family and to all those she has impacted.”

Garner, who had recently given birth to a second child, endorsed Sanders for president before the New York primary in April 2016. In a video released at the time, Garner told the story of how her father died after being placed in a police chokehold, and she praised Sanders for taking the Black Lives Matter movement seriously.

“People are dying. This is real. This is not TV,” said Garner. “We need a president who’s going to talk about it.”

Garner’s endorsement was one of the highest-profile interactions between the Black Lives Matter movement and the Democratic Party — a discussion, often heated, that was rarely echoed in the Republican primaries.

Hillary Clinton, who had helped her husband’s White House promote anti-crime initiatives in the 1990s, was confronted by activists and apologized for a speech in which she referred to some recidivist young offenders as “super-predators.” (One of her first campaign speeches, in New York, had been on the subject of criminal justice reform.) Sanders, who had an awkward interaction with activists at the 2015 Netroots Nation conference, went on to embrace the Black Lives Matter movement and promise a series of reforms if he won the White House.

After Sanders lost the primary, Clinton’s campaign tried, often with success, to align itself with the movement. Eric Garner’s widow, Gwen Carr, endorsed Clinton as one of several “mothers of the movement” who addressed the Democratic National Convention.

But many young black voters and activists remained skeptical of Clinton, a fact that the Democrat’s opponents would exploit in the fall campaign. Clinton’s “super-predators” speech was appropriated by the Trump campaign for “dark posts” aimed at black voters on Facebook. The hack of Clinton campaign chairman John Podesta’s emails, which were subsequently published by WikiLeaks, revealed that Clinton staffers struggled with how to talk about Eric Garner’s death, knowing that his eldest daughter had become a Sanders surrogate.

“I know we have Erica Garner issues but we don’t want to mention Eric at all?” Clinton aide Nick Merrill asked in one March 2017 email about a criminal justice reform rollout. “I can see her coming after us for leaving him out of the piece.”

Garner reacted to the hacked emails with fury, saying that the Clinton campaign had been trying to exploit her father’s death.

The 2016 exit poll revealed a small generation gap in support for Clinton from black voters. Those over 45 supported Clinton over Trump by 81 points, a 90-to-9 margin. Black voters under age 25 backed Clinton by just 76 points, with 6 percent of them picking a third-party candidate instead of Clinton or Trump.