It is a day we will never forget.

"Bang. 911, what's your emergency? I'm at Von Maur and there are shots being fired."
"Yes ma'am. Has anyone been hit?"
"I don't know; I'm hiding in a clothes rack."

As 19-year-old Robert Hawkins walked into the Omaha Von Maur store, he opened fire and killed eight people before turning the gun on himself.

Unfortunately, that isn't the first or last random act of violence that has affected millions around the country. From the campus of Virginia Tech to an Amish school house in Pennsylvania, law enforcement officers from around the nation gathered in Lincoln to learn from these tragedies.

The first 911 call shattered the calm of a quiet shopping day just after 1:30 p.m. on Dec. 5 2007. Then came a second call, then another -- there'd been a shooting.

Omaha police arrived at Westroads Mall.

"It's very chaotic at the start; so much information coming in. The sheer volume of the tragedy, as far as the victims. The whole scope of the tragedy is what surprised me the most," said Chief Eric Buske, Omaha Police Department.

Buske is not alone. Officers across the country are experiencing tragedy more these days shootings. Virginia Tech left 32 dead, and five were killed in an Amish schoolhouse in Pennsylvania. Eight victims were killed at Westroads.

"It can happen here. It did happen here," Buske said.

These incidents raise the question: How do you prepare for the next random act of violence?

"One of the most important things is to train and plan ahead," Buske said.

They can also learn from what's already happened. Law enforcement officers who responded to the three mass murders are now sharing their experiences, trying to find answers.

"The individual in the Amish school was able to back his truck up to the school and casually walk into the school. You're not able to do that in the Omaha area," said Sheriff Tim Dunning, Douglas County.

Officials say Columbine was the beginning of the learning curve. Schools have since locked down, allowing access at only a few doors. Now malls like Westroads are following suit.

"The entrances available to you to walk in have decreased. They hired a lot of off duty law enforcement. I know the Westroads security personnel are now all going through a lot of additional training," Dunning said.

And they hope to someday respond to the one question no one seems to have an answer for.

"I certainly don't know the answer of how you can prevent one person who is a psychopathic killer -- don't know how you stop that person," Buske said.

The conference was set up by the Omaha Police Department and Attorney General Jon Bruning. It's one of the first of its kind in the country. The conference was actually being planned before the Westroads shooting happened.

It was just a cruel irony that the Omaha Police Department was suddenly included as one of the presenters, telling their stories of dealing with tragedy as well.