There are actually 2 witches, not one. And they are invisible, so you need to run around and search for them. Don't spent your time for other beasts - Witch of Hemwick will summon more for you.
This is not a very difficult mission when you know what to do :)

Good luck and Have a nice game!

Bloodborne The Witch of Hemwick fight. Bloodborne The Witch of Hemwick fight tips.

I am Alex68, my channel gaming and fun alex68acmp: http://goo.gl/zCIqIL

1st boss: Bloodborne Cleric Fight: https://youtu.be/ubsj6SE5G8o
2nd boss: Father Gascoigne: https://youtu.be/aG654IgWiTs
3rd boss: Blood-starved Beast: https://youtu.be/-3HlvHuOJ6I
4th boss: Vicar Amelia: https://youtu.be/cvyHp6Y7iHE