Two men in their 30s broke in to Westdale Secondary School overnight, police said Tuesday.
Police arrested the men, each 34 years old, around 3:30 a.m.
"We are in the preliminary stages of investigation and as such information is limited at this time," said Const. Jerome Stewart.
Stewart said it was too early to tell if the break-in was connected to threats made Monday at two local high schools, St. Mary's Catholic and Ancaster High, but said that any connection would be investigated.