Crucifixion used in Judaism before the Romans

"The enemies of the 'furious young lion' were 'hanged alive on the tree', a familiar Hebrew circumlocution for crucifixion."--The Dead Sea Scrolls in English, p. 30 (Referring to the actions of the Greeks)

"Note also that the death penalty of 'hanging' (probably crucifixion) reserved for traitors appears in both TS LXIV, 6-13 and the Nahum Commentary."--The Dead Sea Scrolls in English, page 152, edited by Geza Vermes

"The Nahum and Hosea Commentaries further refer to a bloodthirsty priest, nicknamed the 'furious young lion', who strick Ephraim (Commentary on Hosea) and 'hanged alive'(cruficied) some of them (Commentary of Nahum), applying the penalty prescribed in the Temple Scroll for traitors of the Jewish nation (11QTemple 64:7-8). If the story is inspired by the crucifixion of 800 Pharisees by the Hasmonean priest-king Alexander Jannaeus (Josephus, Jewish War I:97), one would have reason to deduce that Ephraim stands for the Pharisees, Alexander's enemies, and consequently Manasseh would refer to the Sadducees, his supports."--The Story of the Scrolls: The miraculous discovery and true significance of the Dead Sea Scrolls, about page 76

Note also that Vermes was a man of Jewish heritage that was raised Catholic (became a cleric) then converted to Judaism.

Vermes makes similar comments in The Complete Dead Sea Scrolls in English