Jindo, South Korea (CNN) -- Anguished relatives of missing South Korean ferry passengers waited sullenly for answers Thursday as rescuers fought bad weather, murky water, darkness and time to find a way deep into the capsized ship.
Authorities believe 287 people -- many of them high school students on a field trip -- remain trapped inside the five-story ship. At least some, authorities say, could still be alive more than a day after the ship rolled over.
Meanwhile, the ferry's captain is facing mounting questions about the incident.
Among other things, authorities are investigating the possibility the ship was off course when it ran into trouble, as well as reports that few of its lifeboats made it into the water, according to Kim Soo Hyeon, the chief of South Korea's Yellow Sea Maritime Police Agency.
Ferry captain Lee Joon Suk, his head and face covered, broke down in tears when reporters asked if he had anything to say.