Those behind the “elaborate hoax” in a quiet area of countryside outside Ballykelly have been condemned by local politicians and residents.
The Carnamuff and Tirmacoy roads were closed off from Sunday evening until yesterday afternoon after a resident discovered a gas cylinder-type device with wires attached by a wall.
Police moved into the area, and ATO carried out two controlled explosions on Sunday night.
The police helicopter was also deployed.
No-one was evacuated, but a resident said: “Everyone is taken aback.
“We’ve never had any trouble here. We thought we were living in peace, but obviously not.”
SDLP Colr. Orla Beattie said: “There is no support for importing the type of activities carried out by disaffected organisations that live in a past that failed everyone.”
Limavady Area Commander Chief Inspector Sam Donaldson appealed for anyone with information to call Limavady police on 0845 600 8000.