The easiest way to watch the series with official Spanish subtitles ("subtítulos en español") is through major streaming services that host international content:
In S01E01, Chief Inspector investigates the murder of 15-year-old Sara Damiani, whose body is found in a flooded basement. At the same time, Valeria must face her own past as her mother, Lucia, is released from prison after serving 17 years for killing Valeria's father. srt file link, or Thou Shalt Not Kill - Season 2 - Prime Video Thou Shalt Not Kill subtitles Spanish S01E01
: The series is available on Prime Video in various regions. You can check the "Subtitles" menu in the player to see if Spanish is available in your location. The easiest way to watch the series with