The Incheon District Prosecutors' Office conducted the Wednesday raids in and around the capital city of Seoul.
One prosecutor said, "The focus of the probe will be to see if the owner family has accumulated huge wealth by embezzling corporate funds while failing to fulfill its duty of properly managing the companies. Tracing their hidden assets is also needed to pay damages to the victims and their families."
476 people were aboard the Sewol when it sank off the coast of South Korea on April 16. 174 of the passengers and most of the crew were rescued, and 150 people were confirmed dead. 152 people remain missing.
Notable deaths of 2014 [PHOTOS]
Ebola cases top 10,000, WHO report says