"The Panel has found that the investigations have failed to satisfy the requirements of the European Convention of Human Rights," the report read.
The panel added that the investigation into the conduct of the fire service and the police cannot be regarded as independent, given the structural links of both public services with Ukraine's Internal Ministry.
"These concerns again highlight the need for an independent and effective mechanism for the investigation of serious human rights violations committed by law enforcement officers and other public officials," according to the report.
The document added that lack of substantial progress in the inquiry should be attributed to deficiencies in the process of the investigation.
"The Panel considers that substantial progress has not been made in the investigations into the violent events in Odessa on 2 May 2014," it read.
"While this outcome may be explained to some extent by the contextual challenges, the Panel considers that the deficiencies identified in this Report have undermined the authorities’ ability to establish the circumstances of the Odesa-related crimes and to bring to justice those responsible," the report reads.
The IAP was established by the CoE secretary general, "to oversee that the investigations into the violent incidents which took place in Ukraine from 30 November 2013 onwards met all the requirements of the European Convention on Human Rights and the case-law of the European Court of Human Rights," according to the CoE web site.
The IAP’s first report, published in March 2015, found that the Ukraine Prosecutor General Office has made little progress in its investigation of the 2013-14 Maidan protests that left 90 people dead and hundreds injured.