The divers, with oxygen and communications lines trailing, can only see a few inches in front of them in the wreckage of the ship. Most of the victims were high school children, who were told to stay where they were for their own safety.
Most of the bodies found in the last two days had broken fingers, presumably from the children frantically trying to climb the walls or floors to escape in their last moments.
"We are trained for hostile environments, but it's hard to be brave when we meet bodies in dark water," said diver Hwang Dae-sik, as the funerals of 25 students were held near the capital, Seoul.
Prosecutors investigating the disaster raided the home of Yoo Byung-un, the head of a family that owns the Chonghaejin Marine Co Ltd, which operated the Sewol ferry.
They also raided his son's home and the office of a church with which Mr Yoo has been associated, said a prosecutor who did not want to be identified.
The finances of Chonghaejin and its complex share structure have come into the spotlight in recent days. Mr Yoo was jailed for fraud for four years in the early 1990s.
However, it was not clear how significant a development this was. Korean police and prosecutors often carry out dramatic raids to show progress is being made in a high-profile case.
Underwater, at the site of the sunken Sewol, divers are able to work for nearly an hour at a time as long as the oxygen lines do not snag on sharp corners of the ship's internal structure.