SCOTTSDALE, Ariz. -- Five seniors and one former student of Desert Mountain High School were arrested Thursday in connection with two recent burglaries at the school.

Those arrested are 19-year-old Roy VandeWater, who graduated last year; 17-year-old Thomas Coletto, 17-year-old Matthew Hendley, 17-year-old Alexander Troche, and a 16-year-old whose identity CBS 5 is not releasing because of his age.

Police also questioned another senior, 18-year-old Scott Evans.

VIDEO: WatchCBS 5 News report

Investigators said it appears vandalism was the group's main focus, and that no specific person was targeted.

Officers investigating reports of a threat against the school said interviews with students and staff led them to the six young men.

Police said at least one of the suspects was accused of detonating homemade devices in the past.

The suspects were implicated in two recent burglaries that police said may be related to the threat against the school.

In the first, a computer and printer used for making IDs and a school security radio were stolen. About a week later, various chemicals were stolen from a science lab.

At least two of the suspects were tied to the chemical burglary, according to police.

Detectives made contact with each of the suspects at their homes Thursday evening and said they all made varying degrees of admissions to the burglaries.

Police said they recovered the security radio and ID equipment.

Officers served search warrants at the homes of two of the suspects and said they found chemicals and what appeared to be explosive-making materials. Police said the chemicals included ammonium nitrate, which was used to make the explosives used in the Oklahoma City bombing.

One suspect was interviewed and released pending issuance of a complaint. The others were booked on burglary charges and released to their parents. Police said additional charges may be pending.

Investigators said they believe the teenagers were all plotting to start powerful explosive chemical fires using materials stolen from the high school's science lab, and there's evidence they were planning to execute their scheme on Friday on the Columbine anniversary.

At least 350 students were absent from school today -- that's more than than double the usual amount.