Call it the case of the mysterious box-leaver.

Westport Police detectives are searching for two people who have been, well, leaving boxes in the yard of a particular home.

It’s been going on for a year.

There does not appear to be any rhyme or reason for the box-leavings — police said in a Facebook post that it was “on random occasions over the past year on Franklin Street in Westport.”

A video posted by police shows the, um … incident … and indeed, what appears to be a woman can be seen nonchalantly placing a box on the inside of a fence.

“The individual is seen leaving the box and continues walking south bound on Franklin Street towards the Westport Train Station,” police said.

As for what’s in the box — the natural question — it is unfortunately not yet known. Police did immediately not respond to a request for comment on the case.

Anyone with information is asked to contact the Detective Bureau at 203-341-6039.