JERUSALEM — The parents of captive Israeli soldier Gilad Shalit set up camp outside the residence of Prime Minister Benjamin Netanyahu on Thursday, vowing to stay there until their abducted son is freed. They reached the site after a massive rally capped a 12-day march to Jerusalem aimed to pressure the government into doing more to secure their son's release. "It's time to say enough is enough. Four years of hell -- that's too much," the soldier's mother Aviva Shalit told an estimated 25,000 people at Jerusalem's Independence Park. A former head of Israel's Shin Bet intelligence service told the crowd: "Gilad in prison: it's inhuman, it's immoral, it's illogical." The droning of vuvuzelas mingled with Israeli pop music blaring from car-mounted loudspeakers as the marchers made their way into central Jerusalem earlier in the day. Many sported T-shirts bearing an image of the 23-year-old soldier and the words "Gilad is alive." A banner proclaimed "The people have decided: Free Shalit."