Should I talk to my boss about this?

I have worked in a lab for 5 months. Since the work description is not clear cut among 3 of us. so we are all doing the similar tasks. There is a young girl recently started to do less and less. Last week when the group leader asked her to do something while she has just sat there for more than 2 hours, she said she is waiting for me, making it sounds like it is my fault that she did not do her job. Since I was busy at that moment I did not say anything (which I should). But later I talked with the group leader and she seems like totally agree with me (the young girl left early). The next day I asked that young girl what did she mean by saying that she is "waiting for me", she started lying. I did not allow her and immediately pointed out that what she said was not true at all (the group leader was there but she did not say anything, I think she did not want to take a side). And she is apparently very unhappy. The group leader said that we are going to discuss this later but today when I cam these 2 were already in and I sensed the group leader was not happy. Since I have heard that young girl complains about half of the people here which are either trivial or made up stories. So, I worry about this now. I am wondering if it is a good idea to discuss this with my boss.

Anybody (Ge Wei Da Xia), please give some input. Waiting online.


Thanks a million!!!