The cases were handed over to the probe agency through a court directive, after Goa National Students Union of India (NSUI) filed a petition in the Bombay High Court bench here.
Pravin Salunke, Deputy Inspector General (CBI), told PTI today that they were still awaiting notification from Department of Personnel and Training (DOPT), Delhi.
"We will start investigating once we get the notification," he said.
The CBI was expecting the DOPT to issue notification in the last week of May. The three cases allegedly involve eight policemen, who were found having connections with Israeli drug dealer Yaniv Benaim alias Atala and David Driham alias Dudu.
Though all policemen allegedly involved stand suspended, Atala and Dudu are out on bail.
The Goa government, which was initially reluctant to hand over these cases to CBI, had to bow down after High Court order directed it to transfer the cases.
NSUI pleaded handing over the probe to CBI raising suspicion on the way the investigations were conducted by Crime Branch led by Deputy Superintendent of Police Chandrakant Salgaoncar.