St Louis County police responded to the protests and civil unrest that followed the death of teenager Michael Brown in Ferguson, Missouri, with heavy-handedness and encroached on protesters constitutional rights, thereby increasing tensions between the majority white police force and a majority black community, a federally commissioned review has found.

The collaborative review, produced by the Department of Justice’s Community Oriented Policing Services (Cops), also found the department relies heavily on the experience of Swat training and must do more to engage officers in community policing as well as recruiting more black Americans to its ranks.

“While particularly proficient in the area of tactical operations, the department lacks the training, leadership, and culture necessary to truly engender community policing and to build and sustain trusting relationships with the community,” the report states.

St Louis County police department came under heavy criticism for its militarized policing of protests in Ferguson in the wake of the unarmed teen’s death.

The report notes the department “had difficulty anticipating the extent of concern from communities” in Ferguson and therefore “officers reacted to problems instead of taking a proactive approach to preventing them”. It states the department does not have a policy of exhausting all avenues of de-escalation before utilizing tactical Swat responses, which often resulted in “officers with long guns on the front lines and the deployment of tear gas without proper documentation or sufficient warning”.

The report commends certain tactical changes made ahead of the grand jury decision in November 2014 not to indict Wilson over Brown’s death, but found striking evidence that the organisation as a whole was structured in favour of tactical rather than community policing.

Investigators found that while only 6.8% of the 855 strong department has Swat training, those who have this experience accounted for over 25% of officers who were promoted between 2010 and 2015. The report interviews with rank and file officers who said they were told by senior staff there are two types of cops, “those in Swat and those who want to be Swat”.

The Cops report marks the fourth and final federally commissioned review to emanate from Brown’s death, which included a scathing DOJ report on the racial bias endemic in the Ferguson city police department.

As in Ferguson, investigators found that the St Louis County department employed a low number of African American officers. While the black population of St Louis County as a whole is 23.7%, the police department employs just 10.2% black officers. The report calls on the department to actively recruit more black officers across the board.

In a prepared statement St Louis County police chief Jon Belmar said the report served as a “critical analysis of the department”. He argued it was “borne out of an immeasurable amount of scrutiny following the death of Michael Brown” but pledged to “evaluate the recommedations and move forward”.

Asked by the Guardian which recommendations in particular the department would consider implementing, a spokesman responded: “Our department has to review and dissect the report before we comment further.”