What is the forged signature scandal which has rocked TMC?

Trinamool Congress, which has been witnessing dissent after West Bengal election loss, has been rocked by another scandal after at least two MLAs claimed that their signatures were forged on a document endorsing Sobhandeb Chattopadhyay as LoP. MP and Mamata Banerjee's nephew Abhishek Banerjee allegedly signed off on the letter. A CID team has been formed to investigate the charges.