MINNEAPOLIS -- A 911 dispatcher watching real-time footage of George Floyd's arrest in south Minneapolis last month became concerned about the officers' behavior and told a police supervisor she didn't want to "snitch" but thought he should be made aware of the situation, according to an audio recording.

The supervisor promised to "find out" what was happening, but didn't immediately respond to the scene.

The recording of a phone conversation between the supervisor and the dispatcher -- neither of whom was identified -- were released Monday, June 15, on the city's website, along with transcripts of two 911 calls about the incident.

Floyd, 46, died May 25 after being pinned to the pavement by the neck by officer Derek Chauvin, who has since been charged with murder and manslaughter. Three other officers involved in the encounter, Thomas Lane, J. Alexander Kueng and Tou Thao, have been charged with aiding and abetting manslaughter and murder. All four have been fired.

Taken together, the new revelations raised yet more questions about the events that led to Floyd's death on a South Side street corner, which ignited worldwide protests over racial injustice and police brutality.

In the recorded phone conversation, the dispatcher appeared concerned about a police encounter outside Cub Foods, at 3759 Chicago Ave., but told the supervisor she didn't know whether force had been used.

"I don't know, you can call me a snitch if you want to but we have the cameras up for (squad) 320's call, and ... I don't know if they had to use force or not, but they got something out of the back of the squad, and all of them sat on this man, so I don't know if they needed you or not, but they haven't said anything to me yet," the dispatcher is heard saying, using the call sign of police squad being driven by Lane and Kueng.

The supervisor responds: "Yeah, they haven't said anything yet ... just a takedown, which doesn't count, but I'll find out."

"No problem, we don't get to ever see it so when we see it we're just like, well, that looks a little different, but ..." the dispatcher said, her voice trailing off.

"Sounds good, bye," the supervisor said.

The phone conversation, according to the time stamp, lasted less than a minute and ended at 8:31 p.m.

Under the department rules, a supervisor is supposed to be notified any time an officer uses force, with few exceptions, and the supervisor usually responds to the scene.

A police dispatch report data shows that the first supervisor to the scene was Sgt. David Pleoger, who didn't arrive until 8:45 p.m. -- about 37 minutes after officers first encountered Floyd and 14 minutes after the call with the dispatcher ended. Pleoger is a supervisor on the 3rd Precinct's middle watch. It's unclear whether he is the supervisor in the recording.

Department spokesman John Elder declined to comment on the recording, citing the ongoing probe into Floyd's death. But he said that much like other cities, Minneapolis relies on a network of 250-300 cameras spread across the city, called the Milestone system, to help solve crimes and monitor developing events.

"Really what it does is help us have another set of eyes at key locations throughout the city," Elder said, adding that he didn't know what first drew the dispatcher's attention to the Floyd call.

The incident began with police being called about a counterfeit $20 bill and ended with three officers pinning the handcuffed Floyd to the ground, ignoring his repeated pleas that he couldn't breathe.

Locally, the case has raised serious questions about the department's future amid a burgeoning state probe, with activists and some council members calling for the MPD's dismantling in favor of a "public safety system" that is more equitable.

The telephone recording underscored the chaotic nature of the evening of Floyd's death, after which a police spokesman sent out a brief statement saying that Floyd had died from a "medical incident," while a bystander's video of the encounter quickly went viral. Department officials said they were working based on the information they had at the time, and later revealed more details of the incident.

The latest data release also included transcripts of two 911 calls made by bystanders to report the officers involved, including one by an off-duty city firefighter who happened upon the scene.

"Hello, I am on the block of 38th and Chicago and I literally watched police officers not take a pulse and not do anything to save a man, and I am a first responder myself, and I literally have it on video camera," the unidentified firefighter says, according to the transcript. "I just happened to be on a walk so, this dude, this, they (expletive) killed him so ... "

The transcript shows that the firefighter asked to speak with the officers' supervisors to explain the situation, but then the line disconnected. The dispatcher tried to call back several times, but the calls went to voicemail each time.

The transcript of the second 911 call, which came in at 8:32 p.m., features someone reporting that an officer "pretty much just killed this guy that wasn't resisting arrest." When the call taker asks whether there is a supervisor on scene, the caller doesn't respond; eventually, the caller is transferred to a sergeant at the 3rd Precinct.