Giglio , Italy -LRB- CNN -RRB- -- The captain of the cruise ship that wrecked off Italy 's western coast will be questioned by authorities Tuesday at a hearing , his attorney said . Francesco Schettino is under arrest and may face charges that include manslaughter , shipwreck , and abandoning a ship when passengers were still on board , according to Italian prosecutor Francesco Verusio . Schettino could face up to 15 years in prison , he said . At the closed hearing , a preliminary investigation judge will decide whether Schettino will remain detained . The captain has not yet been questioned , but more than 100 witnesses , including passengers and crew , have been interviewed , the prosecutor said . The captain 's attorney , Bruno Leporatti , said in a statement Monday that Schettino was `` shattered , dismayed , saddened for the loss of lives and strongly disturbed . '' But , he said , Schettino is `` nonetheless comforted by the fact that he maintained during those moments the necessary lucidity to put in place a difficult emergency maneuver ... bringing the ship to shallow waters . '' That move , Leporatti said , saved the lives of many passengers and crew members . Italian prosecutors have ruled out a technical error as the cause of the incident , saying the captain was on the bridge at the time and had made a `` grave error . '' Overheard on CNN.com : Worst-case scenario strikes Late Monday , the head of Italy 's coast guard said 29 people remained unaccounted for from the partially sunken cruise ship Costa Concordia -- a sharp spike from earlier estimates of the missing . Coast guard chief Marco Brusco said the whereabouts of four crew members and 25 passengers were unknown , Italy 's ANSA news agency reported . Authorities earlier believed that 16 people were unaccounted for . The Costa Concordia hit rocks Friday night just off Italy 's western coast , leading to what passengers described as a chaotic and surreal scene to evacuate and the deaths of at least six people . On Monday , rescue efforts were ongoing in and around the mammoth vessel , which was listing on its side off the island of Giglio . The search had been suspended earlier in the day because the vessel began to move , said the island 's mayor , Sergio Ortelli . Coast Guard spokesman Filippo Marino said efforts had resumed , adding that rescuers will focus on retrieving the body of a man , presumably a passenger , discovered earlier in the day . However , he said the weather forecast has rescuers worried , as it calls for rising winds . The head of the company that owns the ship said Monday he has not given up hope of finding survivors . `` Hope is the last thing to die , '' said Costa Cruises chairman and chief executive Pier Luigi Foschi . He addressed journalists at an emotional press conference Monday , apologizing repeatedly for the accident . Prosecutors are examining the ship 's data recorder and expect to have results within days , Verusio said . They are also considering whether others may share responsibility for the crash with the captain . Foschi placed blame for the wreck squarely on the captain , however , saying Schettino had deviated from frequently traveled routes . `` The captain decided to change the route and he went into water that he did not know in advance , '' Foschi said . He said the company was limited in its ability to investigate the incident because it did not have the data recorder . Schettino , who has been with Costa since 2002 , had never been involved in an accident before , Foschi said . He downplayed the possibility that alcohol may have played a role in the crash , saying he did not believe Schettino drank , and that all crew were subject to random drug and alcohol tests by Costa Cruises . The company had said earlier that Schettino may have made `` significant '' errors that led to the wreck . `` The route of the vessel appears to have been too close to the shore , and the captain 's judgment in handling the emergency appears to have not followed standard Costa procedures , '' Costa Cruises said in a statement Sunday . The ship had about 2,300 tons of fuel on board at the time of the wreck , Foschi said Monday , adding that so far there was `` absolutely no evidence of fuel leaking into the sea . '' Divers have been searching the skyscraper-sized ship , working underwater in pitch blackness , in hopes of finding the missing . There were roughly 4,200 people on the Costa Concordia when it ran aground . Among those unaccounted for were two Americans . The U.S. State Department identified them Monday as Gerald and Barbara Ann Heil . The U.S. Embassy has requested information from `` anyone with information '' regarding the Heils ' whereabouts , the State Department said . The Heils live in White Bear Lake , Minnesota , according to CNN affiliate WCCO , and have four children and 15 grandchildren . Their daughter , Sarah , told CBS Radio in Chicago that the couple was planning to travel after retiring , WCCO said . The disaster 's impact on earnings will cost the ship 's owner at least $ 85 million to $ 95 million in the fiscal year to November , parent company Carnival Corporation said Monday -- not including `` other costs to the business that are not possible to determine at this time . '' Foschi said passengers would get `` material compensation for their loss , '' but declined to go into details . The ship is expected to be out of service `` for the remainder of the current fiscal year if not longer , '' the company said . Schettino joined Costa Cruises as a safety officer in 2002 before being appointed captain four years later , the company said . Even with its admission that mistakes were made , the Genoa-based cruise company defended the ship 's crew in the face of criticism on the part of some passengers , who said the crew appeared helpless and overwhelmed as passengers rushed for lifeboats . `` It is becoming clear that the crew of the Costa Concordia acted bravely and swiftly to help evacuate more than 4,000 individuals during a very challenging situation , '' the company said , adding all crew members are trained and the passengers earlier took part in an evacuation drill . Survivors have described the scene -- after the ship hit rocks near Giglio , off the coast of Tuscany , and turned over on its side -- as chaos . `` There was no one taking command , '' passenger Lauren Moore told HLN 's Mike Galanos . She said she was having dinner with a group of friends when she heard the crunch of the ship hitting the rock and the crash of plates and glasses falling to the floor . `` It was a terrifying sound and we knew it was n't normal , '' she said . Moore ran to her cabin and then to board a lifeboat . `` It was so chaotic ... Everyone was basically fighting for his or her own life , '' she said . Some passengers braved the chilly water , with a temperature of about 57 degrees , and swam to safety . Others had no choice and fell in . Nighttime temperatures on Giglio have recently dipped below freezing . Authorities have said at least 20 people were injured , in addition to those killed and missing . There were fears the death toll could rise as rescuers searched the ship , which was nearly 50 % submerged and had a gash in its hull , authorities said . Questions and criticism continue about what caused the shipwreck and the adequacy of the response . Speaking on Italian television , the ship 's captain insisted the rocks that the Concordia hit were not marked on his map . `` On the nautical chart , it was marked just as water , '' Schettino said , adding that the ship was about 328 yards -LRB- 300 meters -RRB- from shore . But Coast Guard spokesman Cosimo Nicastro insisted that the waters where the ship ran aground were well-mapped . Local fishermen say the island coast of Giglio is known for its rocky sea floor . Nicastro said the Coast Guard was investigating why the ship took the course it did . `` We know where the ship was , '' he said . `` We know it was too close to the island . ... We do n't know why . '' Built in 2006 , the Concordia had been on a Mediterranean cruise from Rome with stops in Savona , Marseille , Barcelona , Palma de Mallorca , Cagliari and Palermo . The ship was carrying about 3,200 passengers and 1,000 crew members when it ran aground . The dead include two elderly people found Sunday , two French tourists and a crew member from Peru , port authorities in Livorno said . One of the victims was a 65-year-old woman who died of a heart attack , authorities said . The Spanish Foreign Ministry named one of the victims Monday as Guillermo Gual Buades , 68 , saying his family had identified him . CNN 's Livia Borghese , Hada Messia , Jim Boulden , Al Goodman and Richard Allen Greene contributed to this report .