Coalgate: eyebrows raised on Lalit's appointment as CBI

Eyebrows were raised on the appointment of senior advocate U U Lalit to appear for CBI in the Supreme Court in the Coalgate case with an allegation that it was a breach of professional ethics as he was engaged by a private party in coal block allocation matter.
"There is a conflict of interest as U U Lalit, senior advocate, had appeared on behalf of a mining company on November 19, 2012," advocate Prashant Bhushan, appearing for an, NGO Common Cause, told a bench headed by Justice R M Lodha.
Advocate Manohar Lal Sharma, who is also a PIL petitioner in the matter, also claimed there is a conflict of interest as Lalit has appeared in the coal matter for Bhushan Steels Ltd.

While the two advocates made the submission, Lalit preferred not to react and focused himself on the questions raised by the bench also comprising justices Madan B Lokur and Kurian Joseph.
Bhushan, who supplied a note on the matter, has put among other questions: can CBI engage a counsel who has been engaged by a private party in the same case?
Further, is it permissible for an advocate to be appearing for the accused and seek to advice the investigators, i.E.