Lee Joon-seok, third from left, the captain of the ferry Sewol that sank off South Korea, and two crew members prepare to leave a court which issued their arrest warrant in Mokpo, south of Seoul, South Korea, Saturday. Pic: AP.

MOKPO, South Korea (AP) — A South Korean prosecutor says four more crewmembers from a sunken ferry have been detained on allegations of failing to protect passengers.

Senior prosecutor Ahn Sang-don told reporters Monday that two first mates, one second mate and a chief engineer are also accused of abandoning the ship.

Ahn says prosecutors are considering whether to ask a court for a formal arrest warrant that would allow for a longer period of investigation. South Koreans can only be detained for 48 hours without a court-issued formal arrest warrant.

The ferry’s captain and two other crewmembers were previously formally arrested on suspicion of negligence and abandoning people in need.

Sixty-four bodies have been recovered, and about 240 people are still missing.