Cyprus prosecutors filed manslaughter charges against five people on Tuesday over a 2005 plane crash in Greece that killed all 121 people on board in the two countries' worst-ever air disaster.
The names of the five have not been made public but they are expected to attend a hearing to answer the charges early next year, deputy attorney general Akis Papasavvas said.
"The charge sheet was submitted to the court today (Tuesday), and a response to the charges has been set for February 26," Papasavvas told state television.
He would not say who the five people were but said the charges were among the "most serious" provided for under the Cyprus criminal code. The indictment was filed before the district court in Nicosia.
The main charge is manslaughter, which carries a life sentence, and causing death by a reckless, thoughtless or dangerous act, which carries a maximum four-year term.
Relatives of the dead have long called for criminal action against those deemed responsible when a Boeing plane operated by charter company Helios Airways ran out of oxygen and slammed into a Greek hillside in August 2005.
The charges come after three years of painstaking police investigation amid criticism of official foot-dragging levelled by Cypriot relatives of the 121 killed.
Relatives are already taking separate civil action, claiming damages from the state arguing that Cyprus's civil aviation authority was at fault because of negligence by its officials that led to the crash of the Boeing 737-300.
Relatives claim that budget carrier Helios should have had its licence revoked before the crash when it failed to meet certain air safety standards but that an overly lenient aviation authority allowed it to continue operating.
They have also filed claims in Greece, demanding 76 million euros (105 million dollars) from the US aircraft maker Boeing, arguing that confusing sound alarms had contributed to the cutting of oxygen to the cabin and the crash.
Greek crash investigator Akrivos Tsolakis has said that around 200 incidents involving Boeing's air pressure system have been recorded, with disaster only being avoided at the last minute.
The Helios accident made headlines around the world as one of the most puzzling in aviation history.
After leaving Larnaca airport for a flight to Prague via Athens, the plane flew on auto-pilot for more than two hours, ending in wreckage on a rural hillside outside Athens.
When the airliner entered Greek airspace and failed to respond to calls, two Greek F-16 fighters were sent in pursuit and pilots saw that the captain's seat was empty and that a second person was wrestling with the controls.
In October 2006, a Greek commission of inquiry said the Helios pilots had failed to recognise early warnings of a drop in cabin pressure and had omitted to switch pressurisation from manual to automatic in pre-flight checks.
But it also blamed Boeing for taking inadequate measures to rectify similar pressurisation "incidents" on the same type of aircraft.
Most of the victims on board were Cypriots going on summer holiday and some children lost their entire families.
Helios was renamed Ajet Aviation, which ceased flight operations in late 2006.