DALLAS (CBSDFW.COM) – Hundreds attended a public visitation Monday night for slain police officer Rogelio Santander at the Cathedral Shrine of the Virgin of Guadalupe in downtown Dallas.

“The family is hanging in there and giving their last goodbyes,” said Mauricio Garcia, the officer’s uncle.

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He remembers his nephew wanting to be a police officer from a young age.

“That was his dream, and he accomplished his dream,” said Garcia.

Santander was shot and killed responding to a call for backup at a Home Depot, where a suspected shoplifter was being arrested.

Officer Rogelio Santander

The suspect, Armando Juarez, allegedly opened fire, shooting Officer Santander, his partner, Officer Crystal Almeida, and a loss prevention officer, Scott Painter.

Garcia says some family members are hoping an investigation reveals more about the circumstances of his nephew’s death, including how the suspect’s gun was apparently missed in a pat down.

“Because we don’t want another officer to be in the same situation,” he said.

Officers representing departments across the country, including New York, Boston, Detroit and Chicago police, attended Monday’s visitation.

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A number of Dallas city leaders attended as well.

Mayor Mike Rawlings called for greater support of the police force.

“So that we’re not just police tragedy fans, we’re police fans,” he said.

Representatives from Home Depot brought a framed store apron bearing the name Rogelio, and several citizens offered a visible tribute outside the cathedral.

“It was so hard hearing when that was happening on the news and seeing the news. It’s just a sick feeling. So it makes you feel like you’re doing a little part,” said Melissa Gentry, who along with her mother and a friend held blue flags.

Family members and officers who were members of Santander’s police academy class or working in Northeast patrol with him attended a private mass earlier in the day.

“I consider him to be a hero, because that’s what he is,” said Deputy Chief Avery Moore, who oversaw Santander both as a recruit and as a patrol officer.

“We take this job because we love the community, we love the department, and unfortunately sometimes we lose our lives,” he said. “It is extremely difficult when it’s someone you know.”

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Officer Santander’s body will remain under guard at the cathedral overnight Monday.  Tuesday morning it will moved to Lake Pointe Church in Rockwall for a public memorial at 11:00 a.m.  Thousands of people are expected to attend.