Looking for ID of predatory worm

[don at bio-organics.com]

This morning, I observed a gray worm attacking an earthworm on the
surface of my garden soil.

This gray worm is about six inches long, rather thin, limp and flat,
slithers more like a snake than an earthworm, and has a distinct
flexible head that resembles a hammerhead shark in shape.

It was definitely preying on the earthworm.  I've never witnessed this
sort of activity before.  Anyone know the identity of this predator?

I captured it alive and have it available.

Don Chapman
Bio/Organics Supply Center
Camarillo CA
<http://www.bio-organics.com>