Rahway Murder Victim and Killer: Ellen Maher and Wm Froat

Seven years after the murder (in 1887), a woman named Margaret Grace told the detective on the case that she saw a woman at the house of Clinton Froat in the kitchen with William Keetch, the day of the murder. She said her name was Ellen Maher and she had just arrive in the US from Coleraine, N Ireland with the intention of heading west. She also looked like the victim. There was in fact a woman who arrived two months earlier in January, starting from Belfast.

Name: Ellen Maher

New York, U.S., Arriving Passenger and Crew Lists (including Castle Garden and Ellis Island), 1820-1957

Gender: Female
Ethnicity/ Nationality: Irish
Age: 20
Birth Date: abt 1867
Place of Origin: Ireland
Departure Port: Liverpool, England and Queenstown, Ireland
Destination: USA
Arrival Date: 24 Jan 1887
Arrival Port: New York, New York, USA
Ship Name: Britannic

There was no follow up in 1894. And I can't ruler her out with the records. See page 301 of this Google Book:

books.google.ca/books?id=_nybKqeEEZQC&pg=PA301&lpg=PA301&dq=%22case+of+the+unknown+woman%22+%22ellen+maher%22&source=bl&ots=cMXr0Ayqkx&sig=ACfU3U0_k4gVKSV23-GDlLHJRc_3l0AusQ&hl=en&sa=X&ved=2ahUKEwiB6p7goIr-AhVMj4kEHfsRAB0Q6AF6BAgJEAM#v=onepage&q=%22case%