Two men were tied up by masked men in what is thought to have been a "misdirected" robbery.
Three men broke into a property in Mapperley Rise, in the Sherwood area of Nottingham, at 02:00 BST on Saturday.
Officers believe the men were looking for farmed cannabis, and had attempted to rob the wrong property.
Police are trying to find the men, who fled when they realised their mistake. The two men who were tied up are "shaken but otherwise unharmed".
Det Sgt Louise Bradford said it could not be "underestimate[d] how terrifying this ordeal will have been for those affected".