A mysterious loud screeching noise was heard all over Llanelli on Thursday night and was driving people up the wall.
Residents across the town complained of the annoying noise that was "going on for hours" and were left confused as to where it was coming from.
It was believed to have started in the early evening and finally stopped at around midnight.
The high-pitched noise, which was described as "screeching" and "whistling", was heard in the Seaside, Tyisha, New Dock, Bigyn, Llanerch and Pen y Fan areas, until police found the suspected source.
A post about the noise was put on the Llanelli Unseen Facebook page and attracted hundreds of comments.
Melanie Dawn said: "It's driving everyone nuts, nobody seems to know what area it's coming from but it's being heard all over town."
Emma Lanham added: "It's been driving me crazy for hours."
While Kelly Pimm said: "It is really loud in New Dock Road. The other side of the town I could hear it but it was quiet. If I stand in my back garden it's even louder."
Emma Richmond said: "Shut the bedroom windows and it's still really loud, can't deal with this, when will it stop my head's bouncing and my ears hurt."
June Pawelko claimed: "It's been going on four hours. Can't work out where it's coming from."
And Sean Mike Hollyman added: "I just walked down from my house trying to find the source of it. It's doing my head in!"
Dyfed-Powys Police confirmed it received reports of an alarm going off in the New Dock area on Thursday night.
A spokeswoman said: "There was no crime ongoing though and police made enquiries to get hold of the key holder for the property at Nevills Dock, Llanelli."
