Pranksters in east London sparked panic by dumping a fake body made of cardboard tubing and a duvet in the Regent's Canal.
A total of six officers were deployed to the towpath in Haggerston after a string of distressed 999 calls from passers-by on Sunday morning.
Police set up a crime scene, complete with a tent, while an inflatable boat was launched into the canal by a team of divers from the marine support unit.
It took around an hour for divers to drag the 'body' ashore, and they then discovered it contained nothing more than a duvet and toilet rolls.
The hoax drained around two hours from officers' time in total, and acting chief inspector Iain Williams sent an angry messages to the pranksters.
Williams told the Hackney Gazette: “This was a strange incident and unfortunately took away a lot of units that could have been dealing with calls from the public, which is disappointing.
“The object had cardboard-type tubing with a material inside to weigh it down.
“The tubing was bent where limbs would have been, giving further credibility to the initial thought it could have been a body. The shape was covered in material and wrapped in a duvet, which was tied up.
“What may have seemed like a joke initially has actually taken officers away from dealing with domestic abuse incidents, safeguarding missing children, violence and preventative measures due to the rise in moped enabled crime.
“I for one was disappointed to hear about this particular incident, and hopefully the individuals concerned will hear about the impact this has had and consider their actions in future.”