Alright, so nobody has answered this problem so I'll give my answer.

For , both are quadratic residues; therefore is a quadratic residue.

For , neither are quadratic residues; therefore is a quadratic residue.

Therefore we can find such that , i.e. . Since is a unique factorization domain, and since neither factor on the left is divisible by , we deduce that is not prime in , and admits a factorization . Taking norms we get , so .