JINDO, South Korea (CNN) — A sister ship of the sunken South Korean ferry operated by the same company was found to have multiple safety concerns, investigators told CNN.
The prosecutor's office leading the investigation in the southern city of Mokpo said that authorities have been looking at the passenger ferry Ohamana, a ship owned by Chonghaejin Marine. That company also owns the Sewol, which sank off the country's southwestern coast last week with 476 people on board.
The Mokpo Joint Investigation Force Headquarters examined the Ohamana because of its similarities to the Sewol and to get an idea of how the Sewol may have been operating.
Investigators inspected the ship and took away documents from the ships offices Friday. They studied the emergency escape plans and found the following issues:
-- Of the life rafts on board, forty did not work.
-- The emergency slides did not work.
-- There was no equipment to tie down cars.
-- The equipment for tying down the containers didn't work very well.
Like the Sewol, the Ohamana had been modified to add more passengers, the prosecutor's office said.
The Ohamana usually operates between Incheon and Jeju three times a week. According to the ship tracking website MarineTraffic.com, the Ohamana arrived in the port of Incheon on April 16, the day the Sewol sank, and has not left since.
The South Korean Ministry of Oceans and Fisheries said that the Ohamana ceased operating right after the sinking.
Families confront officials
The revelations about the sister ship came the day after angry relatives of missing South Korean ferry passengers cursed government and police officials Thursday for failing to do enough to save the lives of their loved ones as hopes dimmed of finding any survivors.
The relatives berated Fisheries Minister Lee Ju-young and two coast guard officials, accusing them of misleading the public about the operation and of wasting time.
"How can you fool us into believing you were out there trying to save our children?" one mother yelled at the officials.
Also, officials at the South Korean headquarters for the task force coordinating the search told CNN that they believe the body of a boy who reportedly made the first emergency call from the ship after it began to list sharply has been recovered. DNA tests will help officially identify the remains, officials said early Friday.
More than 100 still missing
The ferry Sewol lurched on its side and capsized on April 16 with 476 people aboard, including 325 high school students on a field trip to the resort island of Jeju.
The number of confirmed dead rose to 181 on Thursday, with 121 still missing, according to the South Korean coast guard.
Hopes of finding any survivors in the sunken ferry have all but evaporated following news that divers have found no air pockets on the third and fourth levels of the ship, where many passengers were thought to have been trapped.
Rescuers saved 174 people on the day the ferry sank, including 75 high school students, but no survivors have been found since.
Authorities do not yet know what caused the sinking, but a widening criminal investigation has ensnared the ship's captain and more than a dozen other crew members and led prosecutors to search the offices of the company that owns the ship.
Authorities also searched the offices of 20 affiliated companies and the home of Yoo Byung-un, the man whose family is believed to be behind the company, looking for any evidence of wrongdoing that could have led to the ship's sinking.
Among other things, investigators have said they will look into whether modifications to the ship in 2013 could have altered the ship's balance and contributed to what happened.
Kim Yong-rok, an opposition lawmaker who represents Jindo, an island near where the ship sank, told CNN that modifications to add 117 more passenger cabins to the ship raised the ferry's center of gravity.
Kim said the work on the ferry took place in 2013 after the Sewol was purchased from a Japanese company. The ferry's passenger capacity was expanded from 804 passengers to 921 passengers, he said.
South Korean prosecutors were unable to confirm those details for CNN.
But they are investigating the private organization responsible for inspecting and certifying ships for the South Korean government, which signed off on the work.
Authorities said it didn't appear that the ferry was overloaded, according to figures provided by the company and the South Korean coast guard. But coast guard officials said investigators won't know for sure how much cargo the ship was carrying until it is raised from the waters of the Yellow Sea.
U.S. President Barack Obama offered America's sympathies to South Korea Friday during a diplomatic visit there.
He presented South Korean President Park Geun-hye with a framed American flag that was flown over the White House the same day the ferry sank as a symbol of condolence.
"I'm very mindful that my visit comes at a time of mourning for the people of this nation," he told both the U.S. and the South Korean delegations.
"As allies but also friends, we join you in mourning the missing, and especially the young people."
"President Park, I though it would be appropriate and fitting today to honor the dead and missing if our delegation held a moment of silence," he said.
The two delegations then bowed their heads.
Speaking through a translator, Park thanked him for the gesture, and said, "The Korean people draw great strength from your kindness."
CNN's Nic Roberston and journalist James Yoo reported from Jindo, South Korea, and CNN's Jethro Mullen reported and wrote from Hong Kong. CNN's Michael Pearson, Will Ripley, K.J. Kwon, Steven Jiang, Kyung Lah, Tim Schwarz, Brian Walker, Stella Kim and Judy Kwon also contributed to this report.