While investigators believe that in a tweet Sinitsa called to kill the children of law enforcement personnel who've been involved in dispersing recent unauthorised rallies in Moscow, the blogger insists that his words have been taken out of context.
The latest unauthorised demonstration was held last Saturday and gathered some 750 people.
A wave of unauthorised protests in Moscow began in mid-July after the authorities barred opposition figures from participating in an election slated for 8 September after they failed to gather a sufficient number of signatures of support.
Hundreds of people were detained by police as a result of the rallies. Though most of the arrested were later released, some of the organisers of the protest are to be detained until late September.
In August, the Moscow City Court ruled to allow one opposition candidate, Sergei Mitrokhin, to take part in the upcoming vote.
Commenting on the demonstrations, Russian President Vladimir Putin said that citizens had the right to peaceful protests, and the authorities must abide by this right, but he added that laws can't be broken and nobody was entitled to resort to violence.