A 27-year-old Florida woman who’d built more than 24 pipe bombs was arrested Thursday, after her parents stumbled across the incendiary devices and called police.

In addition to the bombs, Michelle Louise Kolts had gathered smokeless pistol powder, fuse material, 23 different knives, 2 hatchets, nunchucks, 2 BB-pellet type rifles, 6 BB-pellet type handguns, and dozens of books and DVDs about murder, mass killing, domestic terrorism and bomb-making.

“The amount of highly destructive materials we found in this home were astonishing,” Hillsborough County Sheriff Chad Chronister said at a press conference Friday. “If used, these bombs could have caused catastrophic damage and harm to hundreds, even thousands, of people.”

Chronister said a bomb disposal team was required to safely secure the devices from the Tampa-area home, and repeatedly applauded Kolts’ parents for having the courage to call 911.