Concerns about a potentially armed individual prompted a brief hold and secure at Petrolia's high school on Thursday.Lambton OPP said officers responded to a disturbance at around 2:20 p.m.During that time, Lambton Central Collegiate & Vocational Institute (LCCVI) went into a hold and secure, which lasted about 25 minutes.OPP posted the advisory to social media shortly after 3 p.m."One individual is in police custody without incident, and no others are being sought. There is no threat to pub