Is there any flaw in the proof of $-1 = 1$?

Question

We have $i^2 = -1$ where $i = \sqrt{-1}$. Now consider $$\sqrt{-1}\cdot \sqrt{-1} = \sqrt{(-1)\cdot(-1)} = \sqrt1 = 1$$ Which proves $-1 = 1$. Is there anything wrong with the above manipulation?

Answer 1

The equality $\sqrt{a}\cdot\sqrt{b}=\sqrt{ab}$ doesn't hold for $a,b<0$

Answer 2

You can not use the radical properties like you have done in a passage. The product of the square root of $-1$ is not the square root of the product!