What’s Mother’s Day for moms who’ve lost their children to police violence? Maria Hamilton, the mother of Dontre Hamilton, who was killed by a Milwaukee police officer last year, wants to show the country this Saturday. She, along with others who’ve lost loved ones to police shootings, are headed to Washington, D.C., for what they’ve dubbed the Million Moms March.

The gathering was initiated by Mothers for Justice United, an organization that Hamilton founded in the wake of her son’s death. Among those who will be attending are the families of men whose deaths made national headlines, even fleetingly–Michael Brown, Oscar Grant, Tony Robinson, Vonderrit Myers–as well as families of those whose deaths received less public attention. Demonstrators will march to the Department of Justice Saturday to voice demands for justice and racial equity in the name of their sons.

“These are the moms of the stolen lives of loved ones that was taken from them and we’re here today to say that their voice, the victims’ lives, they all matter,” Hamilton said on April 20 at a gathering of Moms for Justice United in Ferguson, Mo. She stood in front of a dozen women who flanked her, holding portraits of sons and relatives who’d been killed by police officers.

Hamilton’s son Dontre was shot by Christopher Manney, a white police officer in Milwaukee, on April 30, 2014. Milwaukee Police ruled after an internal investigation that Manney violated department policy in his initial interactions with Hamilton, which set off an altercation that Manney ultimately responded to with a justifiable use of force. He lost his job.