SOLVED. YA Fantasy about a pair of siblings who can transform into animals. [s]

[Freddy]

This is a book about two siblings, a boy and a girl, who can transform into animals. The boy can transform into a hawk or eagle, while the girl can transform into a cat. I remember thr story being told from the perspective of the girl, with 'letters' from a psychiatrist treating the siblings between each chapter. I don't remember the siblings' names but I think the boy's name may have started with an E. The siblings only have one friend (I think his name is Doug) and he has a crush on the sister. The siblings are suspected of murdering a famous author, who can secretly transform into a snake, just like how the siblings can transform into animals. It is mentioned that both siblings enjoy eating raw meat and tasting fresh blood, like wild animals do. They often have an urge to run out into their back yard, transforming into their respective animal and hunting small prey to eat. When they transform, they shrink and drop their clothes, so they are naked when they become humans again.

These are all the details I can think of so far.

[Becca]

A Fast and Brutal Wing by Kathleen Jeffrie Johnson.

[Freddy]

Becca wrote: "A Fast and Brutal Wing by Kathleen Jeffrie Johnson."

Thank you!