Home and Away star whose character was dramatically unveiled as Witness X has responded to the storyline's shock twist.In scenes that aired in Australia this week, the Summer Bay soap revealed who betrayed Colby Thorne, as the killer awaited trial for Ross Nixon's murder.Witness X turned out to be none other than Willow Harris, played by Sarah Roberts.Willow met up with detective Angelo Rosetta late at night and removed her wire, confirming that she had also covertly recorded Colby's earlier