They mean they’re looking at what laws the guy may have broken, not exclusively 1A. Probable cause gives cops a limited ability to arrest and ask questions later, and public nuisance laws absolutely are a thing.

It should be noted that stadium security initially held him, but the police did not detain him, and have not charged with him a crime because he did not commit one.

Sauce for that last part

Edited cause Sync messed up the link