Who is Billy Ross in Mare of Easttown? His relationship to Erin explained

**WARNING: Spoilers for Mare of Easttown episode six.**

Billy Ross

**WARNING – spoilers for Mare of Easttown’s sixth episode ahead**

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Today’s episode of Sky Atlantic’s Mare of Easttown proved to be a rather revelatory one following the discovery of missing girls Katie and Missy last week, and certainly left us with a number of questions ahead of the big Mare of Easttown finale.

With Mare (Kate Winslet) just about physically recovered from her stand-off with kidnapper Wayne Potts but still haunted by the death of her colleague Zabel, Chief Carter reinstated her on the case and she turned her attention to tracking down Erin’s murderer.

As Mare finally started to get somewhere with her leads, the spotlight on Billy Ross – Lori’s brother-in-law – shone even brighter until he confessed to his brother John, but who is Billy (played by Robbie Tan)? And how is he related to Erin?

Here’s everything we know so far about Billy Ross.

Who is Billy Ross?

Billy Ross is brother of John Ross (Joe Tippett), the husband and high school sweetheart of Mare’s schoolfriend Lori (Julianne Nicholson).

He lives with his father Pat Ross (Gordon Clapp) and has been seen in an increasingly dishevelled state since Mare revealed the news of Erin’s murder. He was asked to break the news of Erin’s death to her father, his cousin Kenny McMenamin, and we learn in the most recent episode that Billy has developed an alcohol problem since her murder.

In episode six, Sore Must Be the Storm, Mare finds a pendant of Erin’s with a date engraved on it matching that of a family trip organised by the Ross family after Erin’s mother died. She tracks it back to the jewellery shop to find that it was bought by Billy, who stayed in the same cabin as Erin at the family reunion.

The same episode sees Pat Ross tell his son John that Billy came home on the night of Erin’s murder covered in blood, after which John confronts Billy and he breaks down, admitting to killing Erin and fathering DJ, Erin’s baby son believed to have been related to her ex-boyfriend Dylan prior to her death.

While Billy admitted to killing Erin and being the baby’s father, we’ve still got one more episode to go and with Erin’s friend Jess giving the police information that pushes Chief Carter to get Mare on the phone, we wouldn’t be surprised if a big ol’ twist was to come our way.

How is Billy Ross related to Erin McMenamin?

Billy and John Ross
HBO/Sky

John and Billy Ross are both the cousins of Kenny McMenamin, Erin’s father.

That therefore means that Billy and Erin are related by blood; Erin is a first cousin once removed to Billy Ross.

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Mare of Easttown continues on Sky Atlantic on Mondays at 9pm. Check out our TV Guide to find something to watch, or visit our Drama hub for all the latest news.