Former FBI executive talks security after assassination attempt at Trump rally in Pa.

As we continue to learn more about the attempted assassination of former President Donald Trump , many questions remain as to how a deadly shooting could happen at such a high-profile event in Butler, Pennsylvania.

"That's the main question I'd like to have answered, how did this person obtain a tactically advantageous position within 150 meters of this subject?" questioned Kyle Vowinkel, a retired FBI Special Agent.

Vowinkel is a former FBI agent of 25 years and is now the founder of Elite Mindsets.

He has worked very closely with the Secret Service and knows how extensive the security planning is for a rally like the one that took place Saturday.

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"I was there at the Boston Marathon bombing. I was the negotiator that talked the bomber out of the boat in the surrendering," Vowinkel revealed.

Leading up to the rally, he says teams are working to identify potentially vulnerable areas. He says the larger the perimeter the more manpower it takes, but that can't be infinite.

Officials also scour social media and conduct a threat assessment before plans are made and finally reviewed by several layers of supervisors.

"Buildings which do provide a line of sight should have been included in the plan to have protection on it. There are some very hard questions they'll have to answer," Vowinkel said.

Several different personnel were involved, including counter snipers who were constantly surveying the area by using binoculars.

"They're not going to have a single degree of responsibility. It'll be 360 degrees. It's a difficult task to be a counter-sniper and find those threats," Vowinkel explained.

At this point, Trump didn't have the same protective measures as the President, which is standard -- but that'll likely change in light of the shooting.

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"Once the RNC or DNC happens and that person is selected as their party's candidate, they receive that second highest level of protection, the first of course being POTUS," said Vowinkel.

While a lot of questions remain, one thing is clear -- the immediate action and bravery from law enforcement.

"These Secret Service agents are men and women with families and children. They again stood in the line of fire immediately to protect that individual. To protect our nation," Vowinkel said.

This remains an active investigation. The FBI is asking anyone with pictures, videos, or information to contact them.

They have received over 2,000 tips so far, but every piece of information counts.

Officials have identified the shooter's weapon as an AR-style rifle.

"Secret Service swift response counter assault team did a fantastic job eliminating that threat quickly because causality would have been much higher had he been able to continue to shoot," explained Vowinkel.