Malcolm Graham, who lost his sister when a gunman attacked a church in Charleston in 2015, speaks about Sunday's mass shooting at a Texas church

Malcolm Graham still remembers the shock when he learned that his beloved sister had been shot and killed at a church in South Carolina two years ago, in a massacre of nine black churchgoers by a white gunman.

So he says he understands the experiences of those who lost loved ones in Sunday morning’s mass shooting at a Texas church, which killed at least 26.

“I know exactly what they’re going through,” Graham tells PEOPLE. “Shock, confusion, disappointment, struggling with faith, some of them may be. Dealing with the death of a family member in such a public way — this is someone dying in the worst of circumstances and it makes it that much worse.”

Graham’s sister, 54-year-old Cynthia Hurd, was one of nine people killed in June 2015, during a Bible study class inside the Emanuel AME Church in Charleston, South Carolina.

While the shooters’ motives appear to differ — Charleston shooter Dylann Roof is a self-professed white supremacist while the Texas shooter was motivated in part by a domestic dispute with his wife’s family — the fact that both attacks were in a house of worship demonstrates a glaring lack of humanity, Graham says.

“Even the church is not a sacred place to escape domestic terrorism,” he says.

Graham says his sister thought of church as a haven: “It’s the place where she felt the most safe … and also the most welcoming. For her to be killed there, it’s heartbreaking.”

Outraged anew that other families are now suffering motivates Graham, 53, to push for legislative action and “to lead a movement that we have to do something in this country.”

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Charleston Church Shooting Graffiti
Cynthia Hurd
| Credit: Adam Ferrell/The Post And Courier/AP
From left: Bailey LeJeaune, 17, and David Betancourt, 18, hold candles during a vigil in Sutherland Springs, Texas, for the victims of a deadly shooting at the First Baptist Church on Sunday,
| Credit: Jay Janner/Austin American-Statesman via AP

Graham, a former North Carolina state senator and city council member, says, “We really have to go to Washington and tell our leaders to get their heads out of the sand.”

Possible solutions, he says, are to close loopholes allowing guns to be purchased without background checks and to limit the number of bullets that guns can fire, among other methods to shore up “weak gun laws,” he says. (It remains unclear how the Texas church shooter purchased his firearms, though authorities have said he had multiple.)

RELATED VIDEO: At Least 26 Dead, Including Children, After Shooter Opens Fire on Texas Church Service

Speaking about the massacre of a country concert crowd in Las Vegas last month, a few weeks before the Texas church shooting, Graham says, “You shouldn’t have the right to buy a semi-automatic weapon that converts to an automatic weapon that shoots 60 people in two minutes.”

Graham says the fact that Kelley is dead allows families to avoid at least one wrenching aspect.

“It spares them a trial,” he says. “Sitting there every day watching him [Roof], listening to him, discovering the evidence, hearing the coroner’s report was just heartbreaking.”

Now, Graham says, it’s time for action.

“It brings back to me, ‘Here we go again’ — whether as a country we are going to do something about it other than thoughts and prayers.”