PORTSMOUTH — A city resident was arrested for allegedly threatening and firing a gun in the presence of three people, including two juveniles, in an apartment late Tuesday evening, according to police. Samuel So, 39, of 100 Ledgewood Drive, Apartment 9 was arrested on numerous charges: one count of criminal threatening, two counts of reckless conduct with a deadly weapon, two counts of endangering the welfare of a child and one count of criminal mischief. Portsmouth Police Department officers were dispatched to the apartment building after a report at 11:57 p.m. Tuesday saying a person was being threatened with a gun. The weapon was later fired and detectives determined two rounds of ammunition were fired through the apartment window, police allege.