MOSCOW — The treason trial of some of Russia’s top cybersecurity officials ended on Tuesday without solving the mysteries at the center of the case: Why had the men been arrested and what, if anything, did they have to do with Russia’s efforts to disrupt the 2016 American presidential election? Was the prosecution driven not by geopolitical concerns but by a businessman’s desire for revenge?

The case began when Russian counterintelligence investigators seized several leading cybersecurity officials in raids conducted in early December 2016. With the arrests coming one month after the American election, speculation swirled that the men had been caught leaking information that helped the F.B.I.’s investigation into Russia’s election hacking.

But no clear evidence of that has ever emerged, and the drawn-out trial wrapped up in a Moscow military courtroom without shedding any official light on the reasons for the arrests or if the timing of them, coming so close to the election, signaled a connection to the Russian meddling.

Under the watchful eye of security forces wearing ski masks, journalists were allowed into the courtroom for the first time on Tuesday to hear the verdict. Speaking for about 10 minutes, a judge convicted the two main figures and sentenced them to lengthy terms in prison for treason, without saying why.