Dodge County sheriff narcotic investigators served a search warrant at a residence on William Way off of the W.P.A. Road on Thursday September 16.
Investigators state their investigation led to the arrest of two (2) people and a large seizure of drugs, cash and firearms.
Investigators found a large quantity of methamphetamines at the residence along with a huge assortment of firearms.
Investigators seized a large quantity of cash and thirty one (31) firearms, including pistols, shotguns and assault rifles.
Investigators also recovered some stolen tools and other items on the property.
Jody Trifiletti and Elizabeth Ann Profit

"...go stop some robberies or home invasions..."
Quoted from article:
"Investigators also recovered some stolen tools and other items on the property."
Unless i'm just stupid, looks like these folks were robbers... and why would they have assault rifles?? In order to perform more robberies or home invasions. Bottom line is, they're criminals. Good job Sheriff and PD.
Let's look at the facts: Convicted felon + 31 firearms + stolen items + large amounts of cash + large amounts of drugs.
Your "gun collector" theory might be plausible in other circumstances, but I'm pretty sure a convicted felon should know better and get rid of said "collection" when he's forbidden to have any firearms. So that coincidence (or whatever you'd like to call it) is out the window.
Secondly, your theory of "they probably purchased stolen items" could be valid if it weren't many stolen goods. The article said "stolen tools and other goods" so we're just supposed to believe that its a big coincidence that this pair purchased several stolen tools and other goods? I could believe that if it were just one or even two stolen items, but it was not.
Now for the large amounts of drugs and cash. These two factors don't strike you as an alert for criminal behavior? I notice you didn't mention them, so I'm assuming you completely ignored these factors in your naivety. What would two people need large amounts of drugs for?
So add up the fact that there is already a convicted felon, who should know better to avoid keeping large amounts of firearms and drugs at his house, but does so anyway. We can either assume that these people are extremely stupid for not realizing their criminal behavior would end them up incarcerated (again) or we can assume they are full blown criminals with no regard for the law.
You can keep being naive (or ignorant) to the facts because you're afraid to admit that not everyone in this world is a good person and deserving of second chances, or you can accept reality and the fact that if there was any good in these people, drugs and crime have taken that away from them.