1971 | 23 Episodes

Season 1 of Investigation Held by ZnaToKi premiered on February 14, 1971.

2002 | 4 Episodes

Season 2 of Investigation Held by ZnaToKi premiered on February 26, 2002.

2002 | 6 Episodes

Season 3 of Investigation Held by ZnaToKi premiered on December 2, 2002.