Who was friend who disappeared in the first book of his dark materials trilogy?

In Philip Pullman's "His Dark Materials" trilogy, the friend who disappears in the first book, "The Golden Compass", is Roger Parslow.

He is Lyra Belacqua's best friend and a fellow student at Jordan College in Oxford. He disappears while exploring the abandoned church with Lyra, and it is later revealed that he was kidnapped by the Gobblers.