The Birthday Present Mystery (Young Cousins Mysteries)

is #1 in the Young Cousins Mysteries series.
==Book Description==
Join the Young Cousins For Fun Mysteries! There's a gorilla with a gift at the door! Sarah-Jane, Timothy, and Titus can't believe their eyes. Then the gorilla starts to sing "Happy Birthday" to someone named Sam. Who is Sam? And who sent the gift? The cousins are sure to find out! Theme verse: "Everything good comes from God, and every perfect gift is from him." James 1:17a.
(Description from paperbackswap.com)