Who is Tulsi Gabbard's 'spiritual guru' Chris Butler?

A probe has revealed that Tulsi Gabbard had close ties to controversial spiritual guru Chris Butler. Butler's Science of Identity Foundation has roots in Hare Krishna movement that gained prominence in US during 1960s-70s under Bhaktivedanta Swami Prabhupada. When Bhaktivedanta died in 1977, Butler stepped away from the Hare Krishna movement to start the SIF, which many describe as cult-like.