Helen Zumbaum will never forget her trip to the mailbox last week.

On Friday afternoon, she was walking from the front door of her house in the Anoka County community of Nowthen when the 55-year-old heard a strange noise and looked up.

Sitting in the grass about 20 feet from her was an alligator.

“At first I thought it was a rag or something else kind of bumpy, but then I looked again and it was like, ‘OK, this is for real,’ ” Zumbaum said. “It was just sitting there like somebody had dropped it off. … I couldn’t believe it.”

Seconds later, the reptile made a mad dash for a nearby pond and Zumbaum was on the phone with the Anoka County sheriff’s office.

A deputy responded to the scene in northwestern Anoka County shortly thereafter, and Zumbaum guided the officer to the location of the sighting.

After walking about 50 feet, the deputy also spotted the alligator — about 3 or 4 feet long — sitting in tall grass, according to an incident report filed with the sheriff’s office.

Once spotted, the alligator again ran for the pond, this time stopping just inches from it, the report said.

After an unsuccessful attempt by the operator of a nearby petting zoo to catch the animal, the deputy called the Minnesota Department of Natural Resources and was advised that alligators are invasive species in Minnesota and should be destroyed.

The alligator was shot twice and killed by the officer shortly after the phone call, the report said.

“That made me sad,” Zumbaum said. “I realize it is a dangerous animal but it really wasn’t the animal’s fault for being there. … I think people get them as pets when they’re small and suddenly they get too big and they don’t know what to do with them anymore, so they just leave them somewhere.”

It’s not clear how the alligator arrived in Nowthen. The operator of the nearby petting zoo said it did not belong to him, the sheriff’s report said.

At least three alligators were spotted last year in Washington County.

Exotic animals are frequently kept as pets, and it’s not uncommon for them to be released into the Minnesota wild.

In a report last year, the Minnesota Herpetological Society said it takes in and adopts out 200 to 300 unwanted or lost animals each year. About 25 percent of those are strays that have been found.

Sarah Horner can be reached at 651-228-5539. Follow her at twitter.com/hornsarah.

Correction: Previous versions of this story contained an incorrect age. Helen Zumbaum is 55.