DSP Bousette Silva today said the viscera was sent to the laboratory almost 20 months after the death, when ideally it should be sent within six weeks.
Police had initially cited "drug overdose" to be the cause of the death but following her sister's protest and pressure from the British authorities, a case of murder has been registered at Anjuna police station here.
Sweeney (35) was found unconscious at Primrose nightclub at Vagator village and died during treatment at a private hospital on April 16, 2010.
The viscera was sent in November 2011 to the Regional Forensic Science Laboratory at Surat.
"Delay in viscera examination results in inconclusive results," Silva said, adding that the Goa Police had tried to get it examined as early as possible but could not get "appointment" from various forensic science laboratories.
After the postmortem at Goa Medical College and Hospital, the forensic experts had reserved opinion on cause of death, waiting for the viscera analysis.
According to Silva, the viscera was to be sent to CFSL Hyderabad, which suddenly stopped receiving samples from Goa. "Thereafter we tried to send it to the laboratory in Chennai, which also refused," he claimed.
Sweeney's sister Maureen has refused to buy the drug overdose theory. British press has quoted her as saying that second postmortem in UK found no trace of drugs or alcohol in the body.
