George Floyd's family urged protesters to remain peaceful in Minneapolis, the city where the 46-year-old man died after his curbside detention this week and where a second day of demonstrations turned into a night of fires, looting and violence.

"I am heartbroken" by all the unrest that erupted Wednesday night and continued into Thursday, said Floyd's girlfriend, Courteney Ross, as she took in the mayhem overwhelming her city for many blocks along or near Lake Street and stretching west to the Uptown business district.

"Waking up this morning to see Minneapolis on fire would be something that would devastate Floyd," said Ross, his girlfriend for the past three years. "He loved the city. He came here [from Houston] and stayed here for the people and the opportunities. … Floyd was a gentle giant. He was about love and about peace."

Ross said she wants everyone who took to the streets "to know that I understand their frustration. … I want people to protest in a peaceful way."

On Monday night, police were called to a store at the corner of E. 38th Street and S. Chicago Avenue on suspicion that Floyd was trying to pass a fake $20 bill. They said the unarmed man from St. Louis Park was resisting arrest.

A witness video documented Floyd on his stomach and handcuffed while white officer Derek Chauvin kept one knee on his neck until he fell unconscious. He was declared dead at HCMC that night. Chauvin and three other officers have been fired as calls for their arrest and prosecution grow louder.

Some of Floyd's relatives echoed Ross' sentiments Thursday through their attorney, Benjamin Crump, who for many years has represented families across the country left mourning the death of loved ones during police encounters.

Crump said in a statement issued after speaking with some of Floyd's relatives that they thank the protesters "for joining them in standing for justice, [but] we also cannot sink to the level of our oppressors, and we cannot endanger each other as we respond to the necessary urge to raise our voices in unison and outrage."

He also said the family intends to have an independent autopsy performed separate from the one being conducted by the Hennepin County Medical Examiner's Office.

Preliminary findings from the county have yet to declare Floyd's death a homicide, saying in a statement that "the cause and manner ... is currently pending further testing and investigation" by the examiner's office, the state Bureau of Criminal Apprehension and the FBI.

He went on to say there would be yet-unscheduled "home-going services" in each state where Floyd lived — North Carolina, Texas and Minnesota — once "the legal matters are done" and the autopsies are complete.

Later Thursday, a protest was planned by a coalition of activist groups outside the Hennepin County Government Center in a call for the four fired officers to be put in jail before charges are filed.

"There is plenty of probable cause to arrest the men who murdered George Floyd," said Michelle Gross, president of Communities United Against Police Brutality. "These men are a danger to society. If this murder had been committed by members of the community, they would be sitting in jail right now awaiting trial."

The coalition added that it wants Gov. Tim Walz to appoint a special prosecutor to take the cases against the officers who would be unaffiliated with the offices of Hennepin County Attorney Mike Freeman or state Attorney General Keith Ellison.

"We have no faith in these agencies to vigorously prosecute police officers," read a statement from the coalition, which is made up of Gross' group along with the Council on American Islamic Relations Minnesota, Justice for Justine Damond Ruszczyk, Women Against Military Madness and others.

Star Tribune staff writer Liz Navratil contributed to this report.