Can you spot that mistake?

Dexter, a math lover, claims that he has proven $e^{2i}=1$, but applying the Euler's formula $e^{ix}=\cos x + i \sin x$, $e^{2i}$ is actually a complex number. In which of these steps does he first make a mistake?

Step 1: As we know, $e^{i\pi}=-1$.
Step 2: Squaring both sides, we get $\big(e^{i\pi}\big)^2=1$.
Step 3: Exchanging the exponents, $\big(e^{2i}\big)^\pi=1$.
Step 4: Multiplying $\frac{1}{\pi}$ at the exponents of both sides, we claim that $e^{2i}=1$.