A man suspected of throwing acid in the face of Bolshoi Ballet artistic director Sergei Filin is being questioned in the Moscow suburb of Stupino, police said.

The New York Times said Tuesday the suspect has not been publicly identified, but has been detained by authorities and his apartment is being searched for evidence he was hired to carry out the assault.

Filin has undergone several operations to save his eyesight and is receiving followup treatment at a clinic in Germany, the Times said.

He suffered burns to his face and eyes when a masked man threw sulfuric acid at him outside his apartment Jan. 17.

The Times said an unknown individual or individuals had harassed Filin by phone and email for weeks leading up to the attack.