Judging from my history in apartments, there has to be more to this than this one incident. If not, then the landlord is an @$$.
In our last place, some kids moved in upstairs. I think the oldest was 17, grandma signed the lease for him.
Even with CONSTANT complaints from us and other neighbors of all night parties, underage drinking, doing drugs, etc. it still took them over 2 months to get them out. The guys below us in our current apartment had the cops called on their parties at least a couple times, and again multiple noise complaints from the tenants. They were there for a year and a half. Now, maybe CO has some stringent laws about eviction, I don't know for sure, but I know that clause is in our lease too.
So either there is more to the story than was in the newspaper, or the landlords are really serious jerks. But I know they have to follow protocol, especially if it is one of the national management/complex owning corporations.