The jet’s downing has increased significance amid the war.

AMSTERDAM — A Dutch court on Thursday convicted three men with ties to the Russian security services and sentenced them to life in prison over the shooting down of a passenger jet above eastern Ukraine in 2014 during a Moscow-backed separatist uprising that foreshadowed Russia’s full-scale invasion of the country. A fourth suspect was acquitted.

The verdict offers a bare measure of justice for the 298 people killed in the downing of the jet, a scheduled Malaysia Airlines service to Kuala Lumpur, Malaysia, from Amsterdam: The men — three Russians and one Ukrainian — were never arrested, are believed to be in Russia or Russian-controlled territory, and were tried in absentia.

Yet the war in Ukraine has given the case greater significance. Support for separatists in eastern Ukraine was a key part of President Vladimir V. Putin’s pretext when he gave the order to invade in February this year, and many bereaved relatives have drawn a direct connection between the downing of the flight and the war. The verdict may also set an example for possible prosecutions of Russian crimes during the current war.

Two Russians — Igor Girkin, a former colonel in Russia’s Federal Security Service and Sergey Dubinsky a former Russian military intelligence officer — were found guilty of murder and downing a plane. AUkrainian citizen — Leonid Kharchenko, who led a Russian-backed military unit — was found guilty of the same charges. All received life prison sentences.

The fourth man, Oleg Pulatov, also a former Russian military intelligence officer, was acquitted because he was considered insufficiently involved in the shooting.

The trial opened more than two years ago as an attempt at assigning accountability in what had long seemed a crime without punishment. On July 17, 2014, an antiaircraft missile provided to separatist forces by the Russian military shot down Malaysia Airlines Flight 17, commonly known as MH17, at cruising altitude over eastern Ukraine. Everyone aboard was killed.

The MH17 crash scattered bodies and wreckage across fields, causing global outrage and prompting Western nations to seek to hold Russia accountable. Most of the victims were Dutch, but the flight also carried passengers from Australia, Britain, Malaysia and several other countries.

There has been much speculation that the people who fired the missile thought they were aiming at a Ukrainian military plane, not an airliner. The separatists had shot down Ukrainian aircraft before.

Russia has repeatedly denied any responsibility in the tragedy, despite evidence that the plane was shot down by a Buk surface-to-air missile sent into eastern Ukraine from a Russian military base across the border, as well as intercepted calls and messages that point to the involvement of Russian-backed separatists.

Instead, Moscow has generated a series of implausible counter-explanations and conspiracy theories that have mostly focused on blaming Ukraine and attacking the legitimacy of the investigation. They included the possibility that the C.I.A. had crashed a planeload of bodies into eastern Ukraine to frame Moscow.

Since Russia vetoed an effort to form a United Nations tribunal for the case, the trial has been held at a local criminal court on the outskirts of Amsterdam, near the sprawling Schiphol airport from which MH17 departed in 2014.