Midrash for Sanhedrin 104:4

אמר רבי אלעזר ברבי צדוק מעשה בבת כהן שזינתה וכו': אמר רב יוסף בית דין של צדוקים הוה

This teaches that when the priesthood is functioning [in the Temple], the judge functions [in respect of capital punishment]; but when the priesthood is not functioning, the judge may not function.<span class="x" onmousemove="('comment',' Thus R. Hama, an Amora living long after the destruction of the Temple, had no jurisdiction for capital punishment. [According to Funk, loc. cit., R. Hama's rigorous sentence was prompted by his desire to combat the Mazdakian doctrine of the community of wives that had found many adherents in his day.] ');">⁵</span>

Sifrei Devarim