USAs new seriesThe Sinnerposes a different kind of murder mystery.

Within minutes of the premiere, star Jessica Biel brutally stabs someone on the beach before shes arrested.

The question is: Why did she commit this crime?

The Sinner - Pilot

Brownie Harris/USA

Its an incredibly visceral and disturbing sequence and one which Biel admits was equally challenging to film.

It was almost an out-of-body experience for me I think, Biel tells EW.

We didnt have a lot of time.

We shot the whole sequence in one day.

We all really knew technically where we needed to be.

Most interesting is that the gore shown in the scene was mostly added later in post-production.

When we were doing it, it didnt seem as awful.

So to watch it back, I was really like, Oh my god.

It was such a bright beautiful day and everyone is just meandering around.

Biel also credits the direction and other actors for adding to scenes surreal terror.

I think youre in such shock when you witness something you dont believe your own eyes.

I understand why people just stand in shock when something crazy happens.

The Sinnerpremieres tonight at 10 p.m.