Her name is Samhita, but she is referred to as "Sam".
sam
Ravi's sister in the "Defective Detectives" series in Tinkle comic book is named Shikha. She is an integral part of the team and often helps Ravi and Rahul in solving mysteries.
a-samhita b-kavita c-raveena d-paromita
Thomas Ravis was born in 1560.
Christian Ravis died in 1677.
Christian Ravis was born in 1613.
Rahul
Thomas Ravis died on 1609-12-14.
Donald Ravis was born on 1940-02-28.
a ravis...
Ravis
I do believe that the first episode they appear in is episode 39, "Defective Detectives", when they introduce themselves. It's a good episode, it really is, at least in my opinion, because Team Chaotix is my favortie team and has Espio, the best in Sonic X. ((just in my opinion.)) You might look Defective Detectives up on Wikipedia, unless you'd rather watch it first.