Final answer:
The lead investigator on the Sleepy Lagoon murder case was Chief of Police Clarence B. Horrall, but this is unrelated to the 1997 Scott Falater case.
Step-by-step explanation:
The police chief who was the lead investigator on the Sleepy Lagoon murder case was not mentioned in the scenario provided. However, if we look at the historical context, the Sleepy Lagoon murder case from 1942 involved the Los Angeles Police Department, and the head of that department at the time was Chief of Police Clarence B. Horrall. It's important not to confuse the Sleepy Lagoon murder case with the separate and unrelated case of Scott Falater, which involved his arrest for the murder of his wife in 1997, where he claimed a sleepwalking defense.