MSU shooting has 'shattered' the community, top prosecutor says

Mark Totten is a leading federal prosecutor with longstanding ties to Michigan State University -- and when he learned this week that the campus was the site of another mass shooting, he immediately got to work.

"I spent a decade on the campus of Michigan State University and taught at the law school, knew the campus well, interacted with hundreds and hundreds of students," Totten, the U.S. attorney for the Western District of Michigan, told ABC News. "It's a place like so many of our universities that has a distinct community. People come there to learn, to build the relationships that are part of learning -- and in an instant, that was all shattered."

Anthony McRae opened fire in two buildings on the MSU campus in East Lansing on Monday night, killing three students and injuring five others, according to authorities. As officers later closed in, he fatally shot himself.

Totten, who is one of the top federal law enforcement officials in Lansing, called the violence "sobering."

"I think it gripped every single person in Michigan and outside of Michigan," he said. "Being a former Spartan, somebody who taught at the university, I think it was especially close to home."

While the shooter is dead, the investigation is both "ongoing and complex," Totten said. Separate from that work, though, is the work of grieving -- and seeking answers to bigger questions.

"There was a vigil on campus that brought hundreds of people yesterday. There were vigils all over Michigan. And I think there's going to be a lot of important questions to ask. I'm going to stay in my lane, which is which is enforcement. That's the role that we play," Totten said. "But certainly there will be others who will be asking some tough questions and trying to think about what can we do going forward to make sure this doesn't happen again?"

He added that authorities are paying very close attention and if there is a role to play, they will do whatever is necessary to help.

Totten said there were more than 19 law enforcement agencies that responded to the shooting -- some who weren't even asked to but felt compelled.

"They just simply dropped everything that they were doing and ran to see what they could do to help," he said.

Now, Michigan mourns.

"It is harder to not know somebody who is affected by this in a fairly direct way than otherwise," Totten said. "Just in the last few days, I've talked with so many friends and colleagues, former colleagues as well, who had kids that were in the dorm rooms, that were in a classroom, that were sheltering in a bathroom for three or four hours."

When Totten visited the campus the day after the shooting, he walked through the crime scene and said it was hard not to become emotional.

"Law enforcement had already done its work gathering the evidence, but everything was pretty much just as it was when the students fled that horrible scene," he said. "And I'll just only say that it was chilling and it was all I could do to hold back tears, honestly, just trying to imagine what those what those students have experienced and what it would be like being a parent of one of those students. And so many parents here in Michigan, of course, were in that situation."