Both boys were born in 1981. While Klebold stayed situated all of his life in Colorado, Harris moved around frequently due to his father being a U. S. Air Force transport pilot. The boys had met sometime while they were at 7th grade in Ken Caryl Middle School. Overtime, they became increasingly close. By the time they were juniors, they were described as inseparable. Harris and Klebold were very unpopular students and frequent targets of bullying. They together got arrested in January 1998, for the breaking into a van and the theft of it's equipment. They got into a diversionary program, to help the boys stay out of any more trouble, while expunging their criminal records if they passed; which they successfully did at the beginning of 1999. By the end of April 1998, the boys began planning the massacre and gathering an arsenal of weapons; and building explosives. They left behind many journal writings and videos, explaining their actions and what they hoped to achieve, like the most deaths in United States history.