In 2001, a floor sander and French polisher was sent to carry out work in a house in an estate off Blackhorse Avenue in Cabra, Dublin. After sanding the two upstairs bedrooms, he began hoovering the dust. The vacuum was plugged into a wall socket behind him in the corner.

As he worked, the hoover suddenly clicked off. Turning around, he saw that the plug had been pulled from the socket. Assuming he had tugged the cable too hard, he plugged it in again—only for it to be pulled out a second time, just a few seconds later.

What unsettled him was that the cable was still coiled neatly on the floor, making it impossible that he had accidentally pulled it loose.

Shaken but determined to finish the job, he plugged the hoover in once more and completed the clean-up. Then he locked the door and left for lunch.

Around 40 minutes later, he returned. As soon as he opened the front door, he was met with the unmistakable sound of the hoover running upstairs—despite the fact that he had unplugged it and locked the house before leaving.

He pulled the hoover out of the room and brought it outside with him. While on the phone to his boss to explain what was happening, he glanced up toward an upstairs window—and froze.

Standing there, looking down at him, were two figures: one adult and one child. He couldn’t make out their features or even their gender, but the silhouettes were unmistakably human. The house was supposed to be empty.

When his boss arrived, the worker refused to go back inside. His boss took over the job, allowing him to leave and finish work elsewhere.

Three months later, at Christmas, the boss admitted something he had kept to himself. After finishing the job and loading his van, and again when he returned to collect the outstanding balance, he too had seen the same two figures standing silently at the upstairs window.