A man fell overboard into the North Sea and died, prompting police to launch a murder investigation.
The victim had been trying to move between two vessels when he fell into the water below on Monday near Hartlepool.
He was rescued from the water by his fellow crew members who performed casualty care until the emergency services arrived.
The unnamed man was pronounced dead shortly after teams arrived, Teesside Live reported.
A North East Ambulance Service spokesperson said: "We were called at 2.16 pm yesterday to assist the RNLI with a rescued patient arriving back at the lifeboat station in Hartlepool.
“We dispatched the air ambulance, a paramedic crew and a clinical team leader."
A spokesman for Cleveland Police said teams are trying to establish the cause of death.
He added: “Just after 2.30pm yesterday police received a report that a crew member from a ship registered overseas had fallen into the water at Hartlepool whilst moving between vessels.
“He was brought out of the water by colleagues and assisted by the RNLI then treated at the scene by paramedics, but very sadly he was pronounced deceased a short time afterwards.
"Detectives from the Homicide and Major Enquiry Team are continuing enquiries in conjunction with other specialist agencies to establish the circumstances of this incident.
“A post-mortem examination will take place in due course to ascertain the cause of the man's death.
"Our thoughts remain with his family and colleagues at this difficult time."
