Week4:Suspicious envelope found in UH

Did you know that suspicious envelope found in UH? Ka leo, a newspaper of UH, reported about the incident like this : Campus Security annouced building closures this Monday morning due to a suspicious envelope at Paradise Palms. Two HPD officers who were present around there adviced a Ka leo staffer that classses in those buildings were probably canceled. The bomb squad arrived around 930am to investigate the alleged bomb.The issue was resolved around noon, although many students didn't mind having class canceled.

I didnt think this sort of big (for me) incident can happen at UH. Also, Im curious that what the incident was eventually going on. This article also stated that : This is not the first time during APEC that a suspicious package has closed down sections of campus. Yet so far none of these scares have turned out to be serious. Im wondering what it means.
Did UH leave these packages, not do something? Then why did this incidents be so serious? Anywise honestly I think this article quotes a couple of uncertain information which Ka leo staffers hear from someone and lacks several neccesary information.

(Words)
squad
(n)a small number of soldiers assembled for drill to a particular task
(ex) The squad attacked the criminal group to save an abducted child.
allege
(v) claim that someone has done sth wrong, typically without proof.
(ex)He alleged that the bomb is fake.