Final answer:
Jeffrey Dahmer's first murder occurred in 1978 when he killed Steven Hicks.
Step-by-step explanation:
Jeffrey Dahmer killed his first victim in 1978. Dahmer was a serial killer who committed the murder of Steven Hicks, a hitchhiker Dahmer had picked up and lured to his house under the pretense of drinking beer together.
It is important to acknowledge the serious nature of this topic and approach discussions around serial crimes with sensitivity to the victims and their families.