Scott Weilage’s finger was poised to hit the delete key that August day.

But for some reason he didn’t trash what seemed like just another bit of junk e-mail — a decision that’s paid off in genealogical gold.

That perceived piece of spam helped open a bank of windows on Weilage ancestral history in America and abroad.

“It’s just uncanny,” the Mankato businessman said of the accidental electronic happenstance that linked Weilage to a treasure trove of family lore.

Here’s what happened:

Weilage was sifting through his e-mails one day when he came upon one from someone named Else Vennemann.

The e-mail was sent to more than a dozen people, including Weilage, who wasn’t familiar with the other names on the address list.

The e-mail said little more than the sender would be coming to Minnesota in October.

But rather than delete the entry, Weilage fired off a brief, flip reply, ending with, “I believe I received this in error?”

A day later, Vennemann responded, writing that her maiden name is Weilage, she is researching for relatives in the United States, and she didn’t know if she and Scott Weilage were related.

Weilage’s curiosity was aroused. He fired off a reply, providing what little information he knew about how his forebears arrived in America.

Vennemann responded quickly, saying she is 71, lives in Germany, has relatives in southern Minnesota, and yes indeed, she and Weilage are related.

“That’s when my jaw dropped,” Weilage said.

Vennemann spoke in her e-mail of her great-grand uncle — Weilage’s great-grandfather — emigrating to America. She spoke of the uncommon surname of Weilage, that it means “wood forest,” and that the family moniker dates back to 1285.

Vennemann also sent the contents of a letter that appears to have been mailed from Germany to the United States circa 1897.