Charges against a 25-year-old man, initially believed to an accomplice, have been dropped.
Defence lawyer Michael Juul Eriksen told the Associated Press his client, who twice had been in Syria, would be released later Friday.
The Jewish school targeted by the girl was Carolineskolen in Copenhagen. She also planned to attack her own school, Sydskolen in Fårevejle.
“The 16-year-old was, according to the indicted, far along in her preparations to bomb two schools. She is charged with having made preparations to make a bomb and for having planned a test explosion,” public prosecutor Lise-Lotte Nilas said.