Divers have sighted debris of AirAsia Flight 8501 in the Java Sea, which is suspected to be the jet’s engine based on the size and shape of the wreckage, an investigator told Channel News Asia on Tuesday. The search for the fuselage and victims of the crash has entered its seventeenth day.

An investigator reportedly said it has not been confirmed if the wreckage spotted is the jet’s engine, adding that there's another “large piece of debris” that may be retrieved in the coming days. Divers have reportedly marked the spot where there is a possibility of locating the plane’s main fuselage. Authorities believe more bodies of victims could be found in the plane’s fuselage. So far 48 bodies have been recovered, with no increase in the number since Friday.

“The past few weeks have been the most difficult weeks of my life since starting AirAsia 13 years ago,” Tony Fernandes, the founder of the airline, which saw its first tragedy with the Airbus A320-200 crash on Dec. 28, said in a statement Tuesday.

Indonesian search and rescue agency on Tuesday reportedly briefed the House of Representatives on the ongoing search and recovery of the victims' bodies. Officials said it was more difficult to find bodies underwater than on the surface, when asked about the chances of finding more bodies, according to Channel News Asia. They added that searchers expected to find the bodies in the plane, but all the bodies recovered so far were spread out in the Java Sea. The search and rescue agency reiterated that its priority was to recover all the bodies.

The second flight data recorder was recovered Tuesday, while the black box was retrieved from the sea on Monday. Investigators have started the analysis of the data that could help determine the cause of the crash. It could take as long as two weeks to download the complete data from the flight recorders.

The plane was on its way to Singapore from Surabaya, Indonesia, with 162 people on board, when it went missing from the radar after the pilot requested a change of course to avoid bad weather. It was traveling at an altitude of 32,000 feet, which was the last known communication from the plane.