Family members and friends say Minneapolis community activist Al Flowers was injured last week when police officers used excessive force during an altercation at his home.

In response, Police Chief Janeé Harteau and Mayor Betsy Hodges called a news conference Sunday in which they provided little information about the incident but asked the public to withhold judgment on the case.

That's a legitimate request, but the public — not to mention this page — would likely feel more confident about the legitimacy of the investigation if it were conducted by an outside entity. As we've argued in other high-profile cases, the MPD should not be investigating the MPD.

In December 2013, we praised Harteau for her plan to farm out some investigations of officer conduct to the state Bureau of Criminal Apprehension. At that time, she said she had faith in her own investigators to do thorough, impartial work. But she acknowledged community concerns about conflicts of interest and agreed that using outside investigators could help build and maintain public trust.

Unfortunately, communication between the state and the MPD broke down, and early this month state officials confirmed that Minneapolis was no longer asking the BCA for expanded assistance. The mayor's office said police would investigate their own critical incidents and seek BCA help only if necessary.

The Flowers arrest appears to be one of those instances. According to his attorney and friends, officers went to Flowers' north Minneapolis home sometime after midnight Saturday to arrest his 16-year-old daughter for an electronic-home-monitoring violation.

Attorney Bobby Joe Champion said Flowers asked the officers to see a warrant, but they either did not or could not produce it. That's when the scuffle occurred — though who started it is unclear. The police report said Flowers assaulted an officer with his fists. The report noted that Flowers was treated but listed only a "prior injury."

Flowers was taken to Hennepin County Medical Center before spending the night in Hennepin County jail for probable-cause assault and obstruction. Photos that showed his head and facial injuries were used in news reports over the weekend.

During their Sunday news conference, Harteau and Hodges said they were frustrated that they were unable to discuss details of the incident because the investigation was ongoing. They should realize that how that investigation is conducted — and by whom — is critical.

Flowers, 55, is a well-known activist within the city's African-American community. He is co-founder of the Minneapolis Community Standards Initiative and the North Side Stop the Violence Committee, and he has served on the now-disbanded Police Community Relations Council. A former mayoral candidate, he's a frequent critic of the MPD.

As recently as last week, he spoke out about the increasing violence in north Minneapolis and criticized the department about the lack of African-American recruits for jobs on the force. He has also sued the city several times.

No matter how good the MPD internal affairs staff members are, it is understandably difficult for the public to accept that they can always be fair and impartial about their co-workers.

To overcome any appearance that Flowers was assaulted because of his activism, the investigation should be conducted externally. Nothing prevents the chief and the mayor from seeking help from the BCA or another local police department or county sheriff's office.

As part of her broader goal to change the department's culture and public image, Harteau has repeatedly said that investigations into officer conduct must be beyond reproach. With that in mind, she should seek an independent investigation in the Flowers case.