PSNI Crime Branch detectives are hunting a gang of masked men who stole six legally-held guns.
The three men, who were armed with crowbars, forced their way into the house at Craigmore Road from a house in Garvagh, Co Derry around 6 am yesterday morning.
A woman in her 20s who lives in the house was tied up and then locked in a bathroom.
She was left badly shaken by her ordeal.
The gang took the guns and left in a vehicle which is still being hunted by police.
Police have appealed for information about the gun theft to contact officers on the 101 non emergency number.