MOSCOW — A court in St. Petersburg on Monday granted bail to three of 30 crew members of a Greenpeace International ship seized during a protest against oil drilling in the Arctic in September. Some see this as a first sign of leniency in an investigation that could continue through the Olympic Games that Russia is hosting in Sochi.

The court ordered the release of the ship’s Russian medic, Yekaterina Zaspa, a photographer who chronicled the protest for Greenpeace, Denis Sinyakov, and Andrei Allakhverdov, all of them Russians. But a different court extended the detention of another crew member, Colin Russell of Australia, for three more months while the investigation continues. The ruling means he could remain in prison until Feb. 24, a day after the Winter Games are scheduled to end.

The dispute over the Greenpeace case has intensified international criticism ahead of a sporting event that has been portrayed as a restoration of Russia’s prestige under President Vladimir V. Putin.