kid's mystery series by an Indian author. group of friends stumbles upon a plan of a heist to steal diamond(s) and/or jewels. The story starts with one of the friends' visiting her uncle

[Nishka]

The book I read was the 2nd in a series.
A group of friends stumbles upon a plan of a heist to steal diamond(s) and/or jewels. The story starts with one of the friends' visiting her uncle who does some work relating to the diamonds/jewels and is also caught up into this. The story is set in New Delhi where the diamonds/jewels are on display in a museum. One of the sub-characters (and one of the suspected antagonist) is a magician/illusionist who floats the Qutub Minar during a performance as some of the protagonists sneak into his tent to investigate.

I read the book in October 2015. I found it in my school library and haven't been able to find it since.

[Rainbowheart]

Was it written in English or another language?

[Nishka]

Rainbowheart wrote: "Was it written in English or another language?"

The book was written in the English language.