PHILADELPHIA (CBS) — Seeing a tragedy unfold at a concert with a large crowd being targeted has many thinking about the security at these types of events.

Philadelphia police say securing big events is something they know how to do and do well. However, dealing with an armed gunman who at elevation requires high-level security, that’s just not possible every day, and even then that security is not fool proof.

“We’re going to look at this closely and look at how we do business,” said Philadelphia Police Deputy Commissioner Dennis Wilson.

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Philadelphia police say they are confident in how they secure large outdoor crowd events in the city, particularly along the Ben Franklin Parkway.

“We have detectives go out to every hotel and every building work with those buildings,” said Wilson.

J.J. Klaver, a former FBI supervisor special agent who spent 26 years with the FBI out of Philadelphia, said the only types of security setups that even deter gunmen from taking high vantage points over large events are ones like we saw for Pope Francis.

“It’s nearly impossible to control all of the potential access points that are elevated,” said Klaver.

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He added, “In a lot of those instances, they are going to put snipers up on the buildings around.”

Klaver said the security was geared to protect the pope more so than the public, and even then it’s impossible to account for every window at every moment in time.

“There’s always going to be risk,” said Klaver. “The risk will never be zero at these types of events.”

As for what police want to see from buildings near places where large events are commonly held, Eyewitness News asked if metal detectors should be used, for example.

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Wilson answered how far do you go when balancing freedom and security.

At least 59 people were killed and more than 520 were injured when gunman Stephen Paddock opened fire from the 32nd floor of a hotel room at a Las Vegas country music festival.

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