Turkish pop singer Mabel Matiz has been subjec to a post-coup investigation for using 1-dollar bills in a 2017 video clip, pro-government Sabah newspaper reported Tuesday.

Having danced with 1-dollar bills in his jacket’s pockets in the video, shot for his track “Ya Bu Isler Ne,” Matiz is accused of aiding the Gulen movement.

The investigation was launched after an unidentified person filed a complaint with the Istanbul’s Public Prosecutor’s Office.

Matiz told prosecutor that he did not intend to “aid the group” and that it was the producer who edited the clip.

According to the Turkish government, one dollar bills are an encrypted messaging system among members of the movement which it accuses of masterminding a coup attempt on July 15, 2016. The movement denies involvement in the attempted putsch.

At least 445,000 people have faced investigation over their links to the movement since the failed coup, according to government sources. Some 150,000 of them have passed through police custody and 90,000 ended up behind bars pending trial.

Law enforcement used 1-dollar bills to jail many people including columnist and Professor Mehmet Altan. The American journalist Lindsey Snell said in August, 2016 that her husband was also detained for possessing $1 bills at their apartment in Istanbul.

The evidence produced by an Istanbul prosecutor to jail NASA scientist Serkan Golge in late 2016 also include one-dollar bills police seized during a search at his brother’s room.