It sure smells like blood! And it is actually blood, but just the slightest bit off. If Terry decides he absolutely must taste test it to make sure, he'll find that it's saltier than blood would normally be.

There's nothing inside the statue if Terry breaks it, everything on the inside a pure white with no hollow spaces, and if he touches the pieces for too long, it'll stain his hands red, although the statue itself remains white. But also, that's somebody's artwork?? Terry????? One of the students will definitely hear that, come rushing in, and will burst into tears when they see what happened. Terry and Sasuke will be forced to sculpt something else out of modeling clay before they're allowed to explore the next school mystery.

In general, every mystery has supernatural involvement that can't be explained, and you're free to make up the details!