One day in June 2018, we were up late working and went to make a coffee, there was an odd noise coming from the empty house next door.

It was around 2.30 in the morning and we went into the alleyway that separates our house from the one next door.

We could hear a machine running, then the machine pumped something into the drain.

We lifted the drain cover and the fumes were very strong, our eyes watered and our noses started running instantly.

We left the cover off and watched and listened from an upstairs window.

We watched and listened for 30 minutes and the machine would run and then pump a strong smelling liquid into the drain, in the thirty minutes we watched, the cycle was repeated three times.

The fumes were very strong so we closed the drain lid. We reported the incident to the Police but they were not interested.

So we bought an audio recorder with an internal battery on eBay and made recordings from different places within our house until we were sure where the noises were coming from.

The noises were coming from underneath our basement floor.

In the far wall of the basement I could see loose bricks and rubble, I carefully dug two 1.5 meter channels into the wall in our basement in an attempt to get better quality recordings.

Over the months we amassed too many recordings to listen to them all.

One of the recordings has 2 foreign men talking and the machine going in the background, the machine had a different pattern than the usual noises, as if one man was instructing the other man on how to run the machine.