警方正在追捕一名在公园里以独行者为目标的行凶者。

The police are hunting a ___serial killer who targets lone walkers in the park.

调查人员认为，一名连环强奸犯要对发生在三个郡的袭击事件负责。

Investigators believe a single ___serial rapist is responsible for the attacks across three counties.

这部纪录片审视了将几起连环谋杀案联系起来的法医证据。

The documentary examined the forensic evidence that linked several ___serial murders.