We reported a few days ago on the mysterious disappearance of Putin critic Leonid Rozhetskin. Some say it was a hoax by the billionaire himself, and it could be, but now the New York Times reports that a second Putin critic has gone missing:

A prominent artist who had run-ins with both church and state in her native Russia after taking part in a controversial exhibition has disappeared without a trace from her new home in Berlin.

The artist, Anna Mikhalchuk, 52, has been missing for nearly a week, with no evidence surfacing up to this point that she is alive, according to a police statement. She left her apartment in the West Berlin district of Charlottenburg on Good Friday at 3:30 p.m. and has not been heard from since, the police statement said.

Ms. Mikhalchuk, who exhibits under the name Alchuk, took part in “Caution! Religion,” a 2003 exhibition at Moscow’s Andrei Sakharov Museum that opponents called “blasphemous.” Shortly after the show opened, six men from an Orthodox church in Moscow ransacked the museum, damaging or destroying many of the works on display.

The museum’s director and a curator were convicted in 2005 of inciting religious hatred. Ms. Mikhalchuk was charged but acquitted. According to her husband, Mikhail Ryklin, a philosopher, she received numerous threats during the investigation and trial but none since they arrived here last year, after he accepted a post at Humboldt University. University officials, with Mr. Ryklin’s help, drafted a letter to the police to highlight possible political or religious motives behind a crime against Ms. Mikhalchuk. “There were religious fanatics who really hated her,” said Mr. Ryklin, 60, in an interview in their apartment.

“For German police to imagine that someone can suffer for artistic activity, for these people its not easy because it can’t happen here,” Mr. Ryklin said.

He said his wife’s disappearance remained a complete mystery, with the police so far finding no evidence of foul play or an accident. He said the police had told him they were doing everything from searching nearby lakes to checking video cameras at train stations.

The police refused to address speculation about Ms. Mikhalchuk’s disappearance. “All we know at this point is that the woman is missing. There is no evidence of a crime at this point,” said Michael Maass, a spokesman for the Berlin police.

Several prominent Kremlin critics have been killed in recent years, including the journalist Anna Politkovskaya and a former K.G.B. agent, Alexander V. Litvinenko. But Mr. Ryklin said that while he and his wife were critical of government policies, they were not political.