Eliza initially claimed that she hardly knew Anna, but it was later revealed that she had placed a large bet on Anna winning a race that she ended up losing. Ultimately, the case's climax would reveal a deeper secret of Eliza's: she was actually a poor girl who originally worked as a market flower girl and who was childhood friends with Anna. Eventually, Eliza's dreams of making something more of herself led her to take lessons on being a "lady", adopting her false persona as a princess.
But sometime prior to the events of the case, Eliza re-encountered Anna at a soiree being held by Lady Highmore, with Anna recognizing her old friend and later talking about Eliza's true identity after getting drunk. Not wanting her secret revealed, Eliza took Anna to the stables to talk to her, but once there, the evil Eliza eventually lost her temper and bludgeoned Anna to death with a stirrup.
Feathers from Eliza's hat were discovered by Viola Pemberton, with this and other clues leading to Eliza's reveal as Anna's killer. After initially proclaiming innocence, Eliza eventually came clean and revealed herself as both an imposter and murderer (dropping her faked accent in the process). Eliza also went on to confess to her impoverished past and friendship with Anna, and how she'd killed Anna to prevent her lie from being exposed. Eliza was arrested and put on trial, where she tried to argue to Judge Justin Lawson that "Eliza Rheinberg" had killed Anna and that all she'd wanted to do was to move herself up in the world. Eliza was ultimately sentenced to eighteen years in prison.
- "Anna and me was best friends growing up. We was always wanting to make somethin' more of ourselves... she with 'er horses and me by taking classes to talk proper like a lady. And I were really good at it! I even fooled everyone into thinkin' I were bloomin' foreign royalty! (Isaac: "So you pretended you were a foreign princess... But I fail to see what your old friend had to do with this farce of yours!") I 'adn't seen Anna in years! But then we bumped into each other at one of Lady 'ighmore's soirées, and she bloomin' recognized me! The likes of me can drink somethin' chronic... But it took just one gin fizz to get that ninny Anna drunk as a skunk! And the drunker she was, the more she talked! I had to shut her up before she told everyone who I really was! So I went to the stables to talk to 'er, all nice and proper like, but then me temper got the better of me... And before I knew it, I'd grabbed the nearest stirrup and begun walloping Anna on the 'ead until she stopped movin'!" (Eliza's confession to masquerading as a princess, as well as to Anna Jewell's murder)