KNOXVILLE, Iowa (AP) — Authorities say an Iowa family’s attempt at a gender reveal party for a soon-to-be-born baby went horribly wrong when a homemade device that was meant to discharge colored powder instead exploded like a pipe bomb, killing a 56-year-old relative.

The Marion County Sheriff’s office says Pamela Kreimeyer died instantly when debris struck her head Saturday before flying another 432 feet and landing in a nearby field in rural Knoxville, about 35 miles southeast of Des Moines.

Kreimeyer was 45 feet from the device when it exploded.

Authorities say family members had been experimenting with explosives in the hopes of posting a colorful announcement on social media.

Family members welded a metal cylinder to a stand and packed it with gunpowder that they thought would send the colored baby powder aloft. But authorities say tape covering the top of the cylinder caused it to detonate like a pipe bomb.