One year after Tyre Nichols died in custoday of a special Memphis police unit known as Scorpion, the U.S. Justice Department is issuing new guidance to police to ensure more care and accountability in those specialized law enforcement teams.

In a report to be made public Wednesday, federal officials call for mayors and police chiefs to assess whether such specialized units are even necessary to solve community problems, to take care that members assigned to them have clean work and disciplinary histories, and to ensure that they're supervised properly.

"Our hope is that the guide is going to help law enforcement avoid the bad and sometimes very tragic outcomes we've seen from such units including what we saw happen a year ago," Associate Attorney General Vanita Gupta told NPR.

The DOJ guide, released by the Office of Community Oriented Policing Services, known as COPS, suggested that the units can serve a laudable purpose, from preventing auto thefts and street violence to arresting particularly violent suspects. But it adds that elected leaders and police chiefs should assess how long they need to operate, and perhaps set term limits based on community needs.

Gupta said she hopes the new report can help managers "ask themselves the right questions at the outset but also ensure that there's management and accountability in place."