Three Cousins Detective Club

#4 The Mystery of the Dancing Angels by Elspeth Campbell Murphy, 1995.

Sarah-Jane, Timothy, and Titus are visiting their grandparents over the summer when their grandmother’s cousin comes over to discuss some information she has found about their family’s genealogy. The kids’ great-great-great-grandfather was a woodcarver, and he did some work in a large house that is now being restored. There is a story that an expensive ruby necklace that belonged to the former owners of the house may be still hidden somewhere on the property.
The prospect of exploring the old house and maybe finding the missing necklace sounds exciting, but the kids also must spend their time looking after their distant cousin, Patience, who is only four years old and has a tendency of getting into trouble.

When little Patience disappears inside the house, the kids are worried, but she soon returns with the answer to a riddle that has been passed down in their family for generations. Dealing with little kids requires patience, but Patience herself notices details in the woodwork in the house that the adults and older children haven’t noticed.
The theme of the story is patience.
The book is available to borrow for free online through Internet Archive.