Regulus looked up to see all three of his companions observing him, clearly wondering about the letter. They knew by now what his mother's owl looked like, and Hogwarts owls were distinctive in their pathetic appearances. Should he show them? Permission to do so was explicitly included in the letter. He had little time to send a letter to Granger right then, and it would be more difficult to bring up should he wait. He trusted them- or rather, he trusted Snape- not to go barreling into this without first making a plan. Snape would certainly agree to help. He was willing to do anything that hurt Sirius.