In 2005, former DIY store manager John White was baffled by strange lights appearing in the sky over his rural home in Denbighshire.
For weeks they appeared as he looked on from his house in Llannefydd near Denbigh, but weren’t stars, planets or any other object he could identify.
Between one and three separate lights would turn up regularly, appearing as bright spots changing colour between blue, red, orange and purple
The unidentified flying objects sometimes seemed to pulse or shimmer and grow in size before shrinking back, or silently moved across the night sky.
He contacted the Daily Post to see if an answer could be found, and had taken hours of footage in a bid to try and establish what they were.
Speaking at the time, Mr White said: “I had just gone into the room to pick up my glasses.
“I looked through the window and I could see this light. I didn’t know what it was.
“I have viewed them through my binoculars. They pulse all sorts of colours: reds, blues, greens and purples. You would also get sparks of white light.
“I contacted the police and they told me to get in touch with the Ministry of Defence. A man there took a look and he had no idea what they were.
“One night, one came down from the east and then it moved slowly across the sky, making no noise. Another night, there were three of them in a line.”
Mr White said other people came to view the lights and had no clue as to their origin.
“My son Karl, who is a sergeant in the RAF, saw them and he didn’t know what they were either,” he said.
At the time, the Ministry of Defence had no comment to make.
Nick Pope, who used to run the MoD’s UFO project desk, said: “When I ran the desk, 80% of all sightings were explicable, there was not enough evidence to make a judgment for 15%, and 5% were unexplained.
“This case certainly sounds very interesting. It seems like it warrants further proper scientific investigation.”
So what could the lights have been?
Mr White could not identify them as a star, planet or other astronomical object. Was there some other natural heavenly body that could account for the lights?
Were they man-made vehicles or objects in the sky which were difficult to identify from his position?
In another North Wales X-File - the Egryn Lights - suggestions for weird lights included marsh gas igniting, luminous insects, the Northern Lights, ball lightning and St Elmo’s Fire - a phenomenon in which luminous plasma glows under certain weather conditions.
Another possible explanation for strange illuminations in the sky are so-called earth lights, which it was suggested could be created in the atmosphere by the friction of rocks rubbing against each other under intense pressure by a mechanism which is still not fully understood.
More out-of-this world theories may suggest alien contact.
Or maybe there is another explanation which accounts for the lights seen near Mr White’s home.