A shocking true crime case unfolds in "Death by Eye Drops." A caregiver is convicted of poisoning her friend, but claims investigators missed key evidence. Hear never-before-released audio of the accused impersonating her victim, and discover the exonerating evidence she allegedly hid. CBS News correspondent Jericka Duncan and "48 Hours" producers delve into this perplexing case, including the judge's surprising statement at sentencing. Watch the full episode and then listen to the in-depth "Post Mortem" podcast discussion.