The death toll from the capsized ferry rising tonight to 181 people - and 121 are still missing.
So why did the ship suddenly take on water?
Investigators are now taking a closer look at renovations made to the ship last year.
A South Korean politician claims the ship's owner expanded the top floor of the ferry, making room for an additional 117 passengers.
The extra weight may have shifted the center of gravity.
First distress call on S. Korean ferry from passenger, not crew, coast guard says
Officials are also looking at whether cargo was properly story in the hold.
Kyung Lah reports on the growing frustration as the search and rescue continues.