CHAPEL HILL, North Carolina — When Yousef Abu-Salha and his youngest sister Razan Mohammad Abu-Salha were just kids, they'd team up against their sister Yusor Mohammad Abu-Salha, the middle child, teasing her until she charged at them and they'd scamper away, laughing.

That memory stands out, he told Mashable. Yousef also remembers helping a friend beat a Pokemon Game Boy game in 4th grade. That friend was named Deah Barakat. Yousef didn't known then that Deah would grow up to marry Yusor and become his brother-in-law.

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Yusor, Razan and Deah were murdered on Tuesday evening, allegedly shot dead by a man named Craig Stephen Hicks, a 46-year-old atheist. Some family members believe the murders were a hate crime, meaning they may have been killed for being Muslim. Hicks' attorney maintains the triple murder was prompted by a parking dispute.

People gather at UNC-Chapel Hill's "Pit" to mourn for Deah Barakat, his wife Yusor Mohammed Abu-Salha and her sister Razan Mohammed Abu-Salha in Chapel Hill, North Carolina, on Feb. 11. Image: The News & Observer, Travis Long/Associated Press

Yousef, like the rest of his family, is heartbroken. But his memories are full of life.

He has so many good memories of Yusor from December alone. She graduated from North Carolina State University. She was accepted into the University of North Carolina School of Dentistry. She married Deah.

"We spent the whole month celebrating her," Yousef said. "I told her it was only going to get better."

Yusor, by all accounts, made for a tough act to follow. But Yousef said his baby sister Razan believed in her own talents, of which there were many.

She was a student in the architecture program at North Carolina State University, a program that Yousef thinks is more competitive than medical school. Razan wasn't much of a studier, but she read and wrote all the time, and had little trouble acing tests.

"I am so blessed to have spent two decades of my life with them," Yousef said. "I want people to remember their smiles, their modesty, their warm yet bubbly personalities, their humility, their compassion, their philanthropy."

Yousef called Deah his most genuine friend. He was elated when Yusor told him Deah was interested in a relationship.

"I told her she got lucky, because he was literally the only guy I would approve of," Yousef said.

The siblings at Yusor and Deah's wedding. Image: Facebook Yousef Abu-Salha

The wedding, he said, was beautiful, and the couple's love was obvious. They did all sorts of charity work, but Yusor and Deah—who was a UNC dental student—also watched sports, traveled, and binged on Netflix.

When people think of the lives of Yusor, Razan and Deah, Yousef wants them to know they are "the true representation of our faith, Islam."

Thousands of people attended a vigil for the three at the University of North Carolina at Chapel Hill on Wednesday, and an equally massive crowd attended their funeral on Thursday. The outpouring of support, Yousef said, underlines the fact that the three were a vital part of so many communities.

Namee Barakat, right, wipes away tears as he and his wife, Layla, left, watch photos projected on a screen during a vigil for his son, daughter-in-law and her sister, who were killed at a condominium near UNC-Chapel Hill, Wednesday, Feb. 11, in Chapel Hill, North Carolina. Image: The News & Observer, Chuck Liddy/Associated Press

"Their deaths were so tragic, the world couldn't help but sympathize with them," he said.

Yousef, who studies at the American University of Antigua medical school, said he is taking the semester off to be with his family. He knows his hiatus is temporary, though, because he said he owes it to his sisters to finish his education.

"I am so grateful to God for blessing me with the time we spent together," Yousef said. "Although we are heartbroken, we are so proud of them."