Sergei Filin, the artistic director at the legendary Bolshoi Theater, was attacked in January by a man who splashed acid onto his face. (Mikhail Metzel/AP)

The January acid attack on Sergei Filin, the Bolshoi Ballet’s artistic director, took a mysterious turn Tuesday after police detained a star dancer and two possible accomplices, without suggesting a motive or lodging charges.

Pavel Dmitrichenko, a soloist who has danced with the Bolshoi for about 10 years, was detained along with two men with no apparent connection to the troupe.

In a statement from the Interior Ministry, investigators said they were working on the theory that Dmitrichenko had organized the attack. Authorities said they suspected that Yuri Zarutsky carried it out. A third man, Andrei Lipatov, who was the first detained Tuesday morning, was described as a driver.

Filin was attacked on a dark, snowy night as he was returning home to his family after spending the evening at a gala attended by many Moscow cultural figures. A man who had covered his face with a scarf called Filin’s name and then threw acid into his face.

The 42-year-old former dancer, severely burned, underwent several operations in Russia in an effort to save his sight, and he was sent to Germany for further treatment. Although he has some vision, the extent of it is not clear. He has said he plans to return to work.

After the attack, the Bolshoi was described as beset by more intrigue and jealousy than even the most tempestuous ballet. Former dancers described bitter competition for roles, which were assigned by Filin, as well as over the company’s direction.

The institution that Russians exalt as an exemplar of their culture and achievement was called “a loathsome cesspool” by Alexei Ratmansky, now artist in residence at the American Ballet Theatre, who said it was being destroyed by a lack of ethics.

Filin had very public rivals in the company, but Katerina Novikova, a spokeswoman for the Bolshoi, said she had not heard of any open conflict between Dmitrichenko and Filin. Dmitrichenko, who has starred in “Ivan the Terrible,” was set to perform next in “Sleeping Beauty.”

Filin had been artistic director for two years and to all appearances had sharpened the company and its dancing. But old disputes dating to the Soviet period over direction and leadership percolated out of public view.

Police said they had picked up Lipatov in the suburb of Stupino, where the Bolshoi owns dachas — summer houses — used by members of the company.

The Russian news media reported that Dmitrichenko owned an apartment in the same building as Filin, a building that is home to many Muscovites from the artistic world. The well-connected Lifenews Web site said that police reviewed phone calls made from the building in January, which helped in their investigation.

“Hopefully, a trail has been found,” Novikova said Tuesday.