This is true story from the newspaper The Cape Times (South Africa):
"For several months, our nurses have been baffled to find a patient dead in the same bed every Friday morning" a spokeswoman for the Pelonomi Hospital (Free State, South Africa) told reporters.
"There was no apparent cause for any of the deaths, and extensive checks on the air conditioning system, and a search for possible bacterial infection, failed to reveal any clues." "However, further inquiries have now revealed the cause of these deaths...
"It seems that every Friday morning a cleaning lady would enter the ward, remove the plug that powered the patient's life support system, plug her floor polisher into the vacant socket, then go about her business. When she had finished her chores, she would plug the life support machine back in and leave, unaware that the patient was now dead. She could not, after all, hear the screams and eventual death rattle over the whirring of her polisher".
"We are sorry, and have sent a strong letter to the cleaner in question. Further, the Free State Health and Welfare Department is arranging for an electrician to fit an extra socket, so there should be no repetition of this incident. The inquiry is now closed." (Cape Times)
The headline of the newspaper story was, "Cleaner Polishes Off Patients"