The Super Puma helicopter, which crashed while practising a routine rescue operation, was found by a deep-diving robot in the early hours of the morning at a depth of more than 2,300 metres (7,500 feet), Spain's defence ministry said in a statement.
“According to images sent by the robot from the boat 'Ares', the four missing crew members are still inside,” the ministry said.
It said it is studying the “viability” of recovering the bodies.
“The helicopter was found at a depth of 2,363 metres, which has complicated the recovery operation,” the statement said.
One crew member survived the accident on March 19.
Naval, police and maritime rescue services had been combing an area 25 nautical miles (about 45 kilometres) from Fuertaventura — one of the largest islands in the archipelago off the northwest coast of Africa — as they tried to find the wreckage.