THE HAGUE, Netherlands (AP) — An international team of investigators building a criminal case against those responsible in the downing of Malaysia Airlines Flight 17 is set to announce progress in the probe Wednesday, nearly five years after the plane was blown out of the sky above conflict-torn eastern Ukraine.

All 298 passengers and crew on board the flight from Amsterdam to Kuala Lumpur were killed on July 17, 2014, when a missile shattered the Boeing 777 in midair sending debris and bodies raining down onto farms and fields of sunflowers.

Ukraine's deputy minister for foreign affairs, Olena Zerkal, told Interfax-Ukraine news agency Tuesday that the investigators will name four suspects. Prosecutors declined to comment on her statements.

The families of those killed will be informed of developments at a behind-closed-doors meeting ahead of a news conference by investigators.

Silene Fredriksz-Hoogzand, whose son Bryce and his girlfriend Daisy Oehlers were among the dead, said it is high time investigators named suspects and set a date for a trial.

"We have been waiting for five years," she said in a telephone interview on the eve of the announcement. "It has to happen sometime."

The investigation team, made up of detectives and prosecutors from the Netherlands, Malaysia, Australia, Belgium and Ukraine, last year said that it was convinced that the Buk missile system used to shoot down flight MH17 came from the Russian army's 53rd Anti-Aircraft Missile brigade, based in the Russian city of Kursk.

Russia has always denied responsibility for shooting down the flight and claimed last year that the Buk missile came from Ukrainian army arsenals. The Netherlands and Australia have said they hold Moscow responsible for providing the Buk missile system used in the downing.

Progress in the criminal investigation has been slow. The Joint Investigation Team, or JIT, appealed in September 2016 for witnesses to provide evidence that could help identify two men heard speaking on intercepted communications discussing movements of a convoy in the days before the attack.

At the time, the JIT said "there is no evidence that these calls are directly related to the shooting down of MH17."

The appeal said one man had the first name and patronymic Andrei Ivanovich and used the call sign "Orion" while communicating. The other communicated as "Delfin" and had the names Nikolai Fyodorovich.

Online journalism platform Bellingcat said last year it had identified "Orion" as a Russian, Oleg Vladimirovich Ivannikov, and said it had determined with "very high certainty" that at the time of the downing of flight MH17 he was an officer of the main directorate of the general staff of the Russian Ministry of Defense, known as GRU, and that he served as a military adviser to pro-Russian separatists in eastern Ukraine at the time the jet was shot down and supervised "procurement and transport of weapons across the Russia Ukraine border."

In December 2017, Bellingcat said that, based on its investigations, it had established "to a high degree of certainty" that the man known as "Delfin" is Russian Col. Gen. Nikolai Fyodorovich Tkachev. He denied having been in Ukraine in 2014.

Bellingcat said in a tweet Tuesday that before the JIT press conference it will publish a report "identifying more individuals involved in the downing of MH17."

If Russian suspects are charged in the Netherlands, it remains to be seen if they ever appear for trial.

The Russian Constitution bars extradition of Russian nationals for trials abroad and says that for crimes committed abroad Russians can only be tried in Russia.