A shooting killed two brothers, one a 17-year-old Memorial High School student. December would deliver another tragedy: A 15-year-old freshman at the school died at home in what Frisco police called a possible double murder-suicide.

A student was fatally stabbed at a Frisco ISD track meet, with another student arrested for first-degree murder.

The 17-year-old accused of fatally stabbing another Frisco high school student confessed to the killing and told police he was trying to protect himself, according to an arrest affidavit.