Switzerland has one of the highest rates of gun ownership in the world, but little gun-related street crime - so some opponents of gun control hail it as a place where firearms play a positive role in society. However, Swiss gun culture is unique, and guns are more tightly regulated than many assume.
Prof Killias was a supporter of the 2011 referendum initiative to keep all militia firearms in a central arsenal - because, he says, of the evidence provided by recent statistics.
"Forty-three per cent of homicides are domestic related and 90% of those homicides are carried out with guns," he says.
"But over the last 20 years, now that the majority of soldiers don't have ammunition at home, we have seen a decrease in gun violence and a dramatic decrease in gun-related suicides. Today we see maybe 200 gun suicides per year and it used to be 400, 20 years ago. "
Prof Killias cannot hide his anger with those in America who use Switzerland to illustrate their argument that more gun ownership would deter or stop violence.
"We don't have a gun culture!" he snaps, waving his hand dismissively.
"I'm always amazed how the National Rifle Association in America points to Switzerland - they make it sound as if it was part of southern Texas!" he says.
"We have guns at home, but they are kept for peaceful purposes. There is no point taking the gun out of your home in Switzerland because it is illegal to carry a gun in the street. To shoot someone who just looks at you in a funny way - this is not Swiss culture!"
