That fact is leading to a review of what happened and renewed calls for giving judges more power to set higher bails.
One pending case against Darrell Brooks Jr included an allegation that he deliberately hit a woman with his car in early November after a fight.
Prosecutors in Milwaukee County on Monday called their bail recommendation “inappropriately low” given the facts of that case and the Sunday crash, and said they would review it.
Julius Kim, a defence attorney and former assistant prosecutor, said the bail could easily have been set more than twice as high.
“He was accused of running over the mother of his kid, and to put it at US$1,000 ($1385) strikes me as low,” Mr Kim said.
“It could have been an inexperienced attorney who happened to be reviewing cases that day.”
Police said Mr Brooks, 39, was behind the wheel of the SUV that sped through the parade route in Waukesha on Sunday, killing five and injuring 48 others.
Waukesha Police Chief Dan Thompson said Mr Brooks was leaving the scene of a domestic dispute that had taken place just minutes earlier.
Mr Brooks has been charged with crimes 16 times since 1999 and had two outstanding cases against him at the time of the parade disaster.
That included resisting or obstructing an officer, reckless endangering, disorderly conduct, bail jumping and battery for the November 2 incident.
Mr Thompson said police were going to recommend he face five charges of first degree intentional homicide, which is punishable by life in prison. He was to appear in court Tuesday afternoon (Wednesday morning AEDT).
Legal experts cautioned one extreme case should not be reason to push for higher bail amounts that would keep poorer defendants behind bars longer while they await trial.
“We don’t want to have a kneejerk reaction here and say ‘Let’s lock up a lot of people pretrial,” said John Gross, a law professor at the University of Wisconsin Law School and also director of its Public Defender Project.
“I’m sure the district attorney’s office is going to look back at this and ask themselves, ‘Did we get this wrong?’
“This is such an extreme incident … could they reasonably expect he would get behind a vehicle and run people down on a parade route?
“What would have alerted you to the capacity he would have had for this kind of violence?”
Some Republicans were quick to jump on the case as an example of a broken legal system.
Republican Rebecca Kleefisch, a former Wisconsin lieutenant governor who is running for governor in 2022, called the killings “yet another avoidable tragedy that occurred because a violent career criminal was allowed to walk free and terrorise our community.”
Republican state Representative Cindi Duchow said she was reintroducing a constitutional amendment that would change the bail process in Wisconsin to allow judges to consider a defendant’s danger to the community when setting bail.
Judges currently are only allowed to consider the possibility that defendants might not show up for a court appearance when setting bail.
“He tried to run over his girlfriend with his car — that’s attempted murder,” Ms Duchow said.
“If you’re a danger to society, you should have to work hard to get out.”
Mr Thompson, the police chief, said there was no evidence the bloodshed Sunday was a terrorist attack or that Mr Brooks knew anyone in the parade. Mr Brooks acted alone, the chief said.
The suspect had left the site of the domestic disturbance before officers arrived, and was not being chased by police at the time of the crash, according to the chief, who gave no further details on the dispute.
Mr Brooks is an aspiring rapper. On a YouTube page, a video that has since been removed showed him rapping in front of a red Ford SUV resembling the one at the parade. The rapper uses the name MathBoi Fly on his Twitter and other social media accounts.
On Sunday, a joyous scene of marching bands and children dancing in Santa hats and waving pompoms gave way in an instant to screams and the sight of crumpled bodies as the SUV sped through barricades and struck dancers, musicians and others in the community of 72,000.
Police identified those killed as Virginia Sorenson, 79; LeAnna Owen, 71; Tamara Durand, 52; Jane Kulich, 52; and Wilhelm Hospel, 81.
Ms Sorenson, Ms Owen and Ms Durand were members of the Dancing Grannies club, and Hospel helped out with the group.
“It looked like dummies being thrown in the air,” said Nicole Schneiter, who was there with her children and grandchildren.
“It took a second to register, like, ‘Is that what we really just saw?’ And then you looked in the road and there were just people laying in the road.”
At least nine patients, most of them children, were in critical condition Monday at two hospitals, and seven others were reported in serious condition.
A pair of clergy solemnly read the names of those who died. Volunteers handed out sandwiches, hot chocolate, and candles at the vigil, which was attended by interfaith leaders and elected officials.
“We are parents. We are neighbours. We are hurting. We are angry. We are sad. We are confused. We are thankful. We are all in this together. We are Waukesha Strong,” said a tearful Amanda Medina Roddy with the Waukesha school district.
The chief said police weren’t pursuing Mr Brooks before he entered the parade route, but n officer did fire a shot to try to stop him. The officer stopped firing because of the danger to others. Mr Brooks was not injured.