Police detained Reznik for allegedly provoking a street fight as he left his office in the early-morning hours of March 3. A court has since charged him with verbally and physically assaulting a police officer and ordered that he remain in provisional custody for at least two months.
The Yabloko party, together with human rights campaigners and a number of cultural luminaries, has cried foul and called for Reznik's release.
According to his own version, the 33-year-old politician was arrested and beaten up by police while trying to pacify a scuffle that had broken out outside his office building.
"Maksim Reznik is well-known for being a harsh critic of Governor Valentina Matviyenko," Yabloko leader Grigory Yavlinsky told reporters shortly after the incident. "We would not like to think that the inappropriate, crude police decision to sentence him to two months in pretrial detention was ordered by the governor or her entourage."
The timing of the arrest certainly invites questions. It came just after Reznik had spent the day collecting alleged evidence of voter fraud in the presidential ballot. And it came just before a March of Dissent opposition rally planned in St. Petersburg on March 3 to protest the election results.
Observers like Yevgeny Volk, of the Heritage Foundation think tank, say Reznik's arrest fits into a broader Kremlin effort to ensure a smooth, scandal-free handover of power to Medvedev.
"I think it is part of a campaign that was aimed at neutralizing any criticism of the election as not very free and not very fair," says Volk. "During Soviet times, authorities carried out preventive cleansings in Moscow ahead of high-profile events. People who could potentially pose a threat to the regime were arrested."
Reznik is not the only opposition figure to have been conspicuously absent from the political arena on March 2.
Oleg Kozlovsky, the leader of the anti-Kremlin Oborona opposition youth movement, was serving an involuntary term of military duty away from Moscow.
He says a policeman accompanied by what he describes as two plainclothes security officers picked him up on December 20 outside his Moscow home and took him to an army enlistment office.
"I went through the medical commission very quickly, without having to queue, almost running," he tells RFE/RL's Russian Service. "Then I was told that I was being drafted into the army, which was a big surprise for me because it had no legal basis. The only explanation I was given was: 'We served in the army, now it's your turn.'"
Kozlovsky, who previously had been partly exempted from service due to chronic health problems, was immediately transferred to a military unit in the city of Ryazan, some 200 kilometers south of the capital.
"There, I heard bits of conversation between the army officers who had brought me and officers from one of the military units," he recalls. "They were saying that I had to be isolated, that I was from some kind of 'Oborona,' that I had to be put far away. They recommended a unit located near a village called Dubrovich in the Ryazan region, some 30 kilometers way from Ryazan, that you have to get to by following an isolated track in the forest. About 15-20 soldiers serve in that unit."
Kozlovsky was released from the army on March 4 -- immediately after the election and the Moscow March of Dissent, in which his fellow activists planned to participate before it was dispersed by riot police -- after serving just over two months of his imposed one-year military service.
Another vocal Kremlin critic, former Arkhangelsk Mayor Aleksandr Donskoi, spent March 2 in jail, awaiting a verdict on charges of abuse of office.
Aleksandr Donskoi after his detention in 2007
Donskoi's legal troubles started after he traveled to Moscow in late 2006 to publicly announce his intention to run for president in the March 2008 presidential election.
In July 2007, police burst into his Arkhangelsk apartment, dragged him outside in his underwear, and threw him in jail to face charges of using city funds to pay for private bodyguards.
But on March 6, after eight months in pretrial detention, Donskoi was suddenly released. Volk, of the Heritage Foundation, says the timing of such decisions is "no coincidence."
If the legal attack against the 37-year-old Donskoi was aimed at forcing him out of the political arena, it has been successful. Today, the man whom veteran Russian rights activist Lyudmila Alekseyeva has called a political prisoner says he is abandoning politics.
"I probably can't inspire anyone now, I can't tell people to go into politics and stand up for their ideas, because I'm scared for other people," says Donskoi. "I wouldn't wish anyone to go through what I endured in jail -- the humiliations, the mockeries from prison and law enforcement officials. In jail, I was treated worse than an animal, like some kind of object that you can kick, move around, isolate in a separate cell."
RFE/RL's Russian Service contributed to this report