A plastic arm on the M62 motorway caused turmoil after drivers believed it was a “severed limb”.
Part of the road was closed as officers searched for the grizzly appendage.
However eventually two council workers called into say that they had removed the arm and taken it to a local police station.
Police said it had caused “traffic chaos and a huge expense”.
Det Insp Tom Keaton said: “This was treated as a major investigation that tied up large amounts of resources and impacted on all areas of policing response in Knowsley.
“We don’t know how this plastic arm came to be in the middle of the road, whether it was placed there deliberately or whether it had fallen out of the window of a passing vehicle.
“However, Merseyside Police put a lot of resources into this incident and not only has it caused expense both in terms of time and money it was also extremely upsetting for the drivers who saw the plastic arm in the road.”
Well, at least no one came to any arm!