This story prompts more questions than answers.

A man who was magnet fishing off the Sixth Street Bridge locked on to something that was kind of surprising, considering it was a German mortar shell from World War I.

The antique explosive was described as a German Granatenwerfer, a mortar shell used in combat in World War I. Not sure if it was a dud or not, police munitions experts have safely stored the device until they can detonate it using C4 explosive.

Joseph Alexander found the device while magnet fishing Tuesday. After getting it out of the water and posting photos of it online, he contacted authorities.

Alexander's friends on Facebook immediately agreed on what it was -- a grenade, specifically as 'Jerry' said,

Looks like a Priest Mormer ww1 German grenade. Shame that it has to be destroyed...

A police officer quickly confirmed both facts -- it WAS a grenade and it would have to be destroyed.

“‘I have to call the bomb squad,'” Alexander told WOOD-TV 8 News the officer told him. “They sent over an undercover vehicle and confirmed it was live, full, and they boxed it up, put it in a yellow bag, put it in the truck and took it out to what they called the field to detonate.”

Alexander called it his “first cool find so far” while magnet fishing, which he only took up as a hobby about a month ago. He had found knives before.

“I didn’t think anyone would throw a live grenade in the river,” he told WOOD-TV. “And for a second there, I was questioning if I was even right.”

Which leads me to the following questions:

What is magnet fishing and what are looking for when you do it? What are some of Joe's other 'cool finds'?

And, why would anyone bring a mortar shell back from the war as a souvenir? It seems if you dodged those successfully during a war, you'd want to stay as far away from them as possible.

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