A 16-year-old girl and a 16-year-old boy were arrested on back-to-back days for making threats to shoot up Ferndale High School, officials said.

A note threatening to shoot up Ferndale High School was found one day after a 16-year-old girl was arrested for making a separate threat that closed down the middle and high schools.

A 16-year-old girl was arrested for making threats that led to classes being canceled at two Oakland County schools on Monday.