It couldn't be.
He never would of thought, not in a million years, that Goku was capable of hurting someone.
He'd been shocked when he'd seen Goku's expression. The youth had looked like he'd been hit by a bus, his skin pale and his eyes wide. In those moments, Sanzo had been so confused by the other's reaction.
However, when Goku had turned and run away, the realization hit Sanzo suddenly. He'd gone to follow the other, but his steps faltered when the thought came to his mind.
Hazel-brown eyes, that shone gold when Goku was happy.
Messy brown hair that refused to be tamed, the right age and sexuality, couldn't be found in a school because he hadn't gone.
Sanzo would of never have thought it, if it hadn't been for Goku's reaction.
It was impossible! How could he even think that Goku could be a killer? Goku was about as innocent as they came, sweet and kind and funny. Goku had said that he'd never had a boyfriend before, and Sanzo believed him. The brunette wore his emotions plainly. Sanzo would of been able to tell if he was lying.
Wouldn't he?
If Goku had killed Yamakura, IF, then Sanzo had to get to the bottom of it. He had to know the truth, had to find some way to prove Goku was innocent. This was more than just a grade now. It was his life... and the life of the person he was in love with.