New Delhi, Sep 2 (IANS): Delhi Deputy Chief Minister Manish Sisodia on Wednesday expressed his displeasure over the Anti-Corruption Branch's reported decision to close the investigation in the multi-crore CNG scam when a government panel was already probing the case.

In a letter to the vigilance department, Sisodia said he was "surprised" over the development and questioned why the anti-graft body was "hurrying up" in filing the charge sheet.

The vigilance department comes under the the ACB.

The Aam Aadmi Party leader was reacting to the media reports claiming the ACB was in the process of finalising the charge sheet in the scam.

"I am surprised that within a few days of setting up this Commission of Inquiry, the ACB has decided to close the investigation by filing the charge sheet," Sisodia wrote in his two-page letter.

"The first question is that who within ACB is speaking to the media and leaking information when the investigation is still going on?"

"Why is Anti-Corruption Branch is hurrying up in filing of the charge sheet. Has it examined the allegations made by CBI in its report against the Lt. Governor."

The scam took place during the chief ministership of Congress leader Sheila Dikshit.

The probe in the CNG fitness scam has pitted the the AAP and the central governments against each other with the union home ministry declaring the commission of enquiry set up by Delhi government as legally invalid.

The centre had also stated the the probe will be continued by the ACB. However, the AAP had replied, it wont pay heed to centre's decree.

The control of the Anti-Corruption Branch is one of the contentious issues between the Delhi's AAP government and Lt. Governor Najeeb Jung.