Iowa State University police arrested a 21-year-old student today (Monday) and charged him in connection with pop-bottle bombs found near a student residence last Thursday. Commander Gene Deisinger says a custodian was cleaning up trash outside the student apartment complex when she found some exploded plastic bottles and then came upon one still intact.The custodian had heard about a bottle-bomb incident last week in Urbandale, and was concerned this could be another one so she called the campus authorities. Deisinger says after an investigation, ISU police arrested 21-year-old Thomas Hoff, who lives in a third-floor apartment in Frederickson Court in Ames. The charge was a serious misdemeanor, reckless use of fire or explosives. Deisinger says Hoff lives in an apartment complex adjacent to where the bottle bombs were found. A junior in Animal Science, Hoff is originally from Schaumburg, Illinois. Deisinger says Hoff made three of the bottle bombs and dropped them, setting off two. One that didn’t go off is the one found last week. While he doesn’t want to speculate on the motives, the commander says it’s pretty clear Hoff had no intent to harm anyone or cause damage, and just wanted to see what would happen.