Police have said that the presence of a "kill cord" safety device will form a "key focus" of the investigation into a boat accident in which two people died in Padstow, Cornwall.
The cord's purpose is to ensure that a boat's engine is cut if the person in control goes overboard.
Det Supt Jim Colwell from Devon and Cornwall Police told reporters:
"Clearly the reasons why the boat didn't stop when it otherwise should have done, when there was nobody left on it, is a key part of our investigation.
"The kill cord - the presence of, the state of, and how it was attached or otherwise - will be a key focus of our investigation."
A father of four who was killed in a speedboat accident along with his eight-year-old daughter doted on his family", his brother has said.
Two people have died and another four people have been injured in a speedboat accident while on holiday in Cornwall.