Doctors said that Chandru Gawas, 33, died of multiple organ failure.
North Goa Superintendent of Police Arvind Gawas told reporters that a case of unnatural death has been registered at Panaji police station.
"We will carry out an investigation to probe what led him to commit suicide," the officer said.
Special Judicial Magistrate (SJM) Maria Mascarenhas, on Monday recorded his dying declaration wherein he allegedly named three senior officers of Crime Branch. He reportedly alleged that the officers would constantly harass him for work.
SP Gawas said he was yet to receive the magistrate's report.
Gawas consumed the ratol poison paste last Friday allegedly due to harassment by his seniors. He was rushed to a private clinic after he started vomiting blood, from where he was shifted to GMC as his condition worsened.
(Reporting by John Edwards)