Aired on Bissextile Day (Leap Year Day/February 29th). The only time this happened during the 5 seasons this series ran.
During the last 10 minutes, when Cannon is trying to convince "The Doc" to come clean, he mentions the possibility of the gas chamber. But, in 1971, the year before this episode aired, all death penalty laws were struck down in the United States and executions would not resume until Gary Gilmore was executed in 1977.