The recent arrest of Darrell Brooks, a 39-year-old career criminal who had just been let out on a $1,000 bail days before allegedly murdering six people in a Christmas parade, left many Americans wondering how he was out on the streets in the first place. 

Communities nationwide have been outraged in recent months by a string of high-profile cases in which criminals with lengthy rap sheets allegedly committed heinous acts.

Here is a look at the circumstances leading up to Brooks' release, as well as other recent cases involving violent criminals. 

Waukesha Christmas parade attack

Waukesha suspect Darrell Brooks mugshots

A lineup of multiple mugshots showing Waukesha suspect Darrell Brooks over the years. (Waukesha PD/AP)

Darrell Brooks was arrested Nov. 2 for allegedly assaulting and running over the mother of his child, then released on just $1,000 bail on Nov. 16, less than a week before he allegedly plowed through a Christmas parade in Waukesha, Wisconsin, killing six people and injuring dozens of others. 

Just months before that, he was freed on $500 bail in February for allegedly firing a gun at his nephew. 

The 39-year-old convicted sex offender has a lengthy criminal record dating back more than two decades, including charges for weapons offenses, assault, battery, drugs, bail jumping and statutory rape. 

WAUKESHA PARADE SUSPECT DARRELL BROOKS SAYS HE FEELS 'DEHUMANIZED,' 'DEMONIZED' IN FIRST JAILHOUSE INTERVIEW

Milwaukee County District Attorney John Chisholm appeared before a Milwaukee County board committee on Thursday, saying that the bail figure was requested by a young, overworked assistant district attorney "who made a mistake."

"That's it," Chisholm said. "It's human error, and it set in motion a chain of events that is a human tragedy."

Brooks is now being held on $5 million cash bail and is facing six counts of first-degree intentional homicide, among other charges. 

Homicide of 14-year-old Ryan Rogers

Ryan Rogers was allegedly killed by Semmie Williams Jr in Palm Beach Gardens

Ryan Rogers, left, was allegedly killed last month by Semmie Williams Jr., a Florida man with a lengthy criminal record.  (Palm Beach Police Department)

Semmie Williams Jr., a 39-year-old man with a 16-page rap sheet in Florida, was arrested Wednesday in the unprovoked stabbing death of 14-year-old Ryan Rogers. 

Rogers left his home in Palm Beach Gardens for an evening bike ride on Nov. 15 but never returned, prompting his family to report him missing later that night. His body was recovered on the side of a road the next day. 

"We do not have a motive in this case, and I would best describe it as an innocent child victim having a chance encounter with a very violent criminal," Palm Beach Gardens Police Chief Clinton Shannon said at a press conference Thursday. 

SC SHERIFF WARNS CHILD PREDATORS AFTER 5 STING ARRESTS: 'IF YOU HUNT OUR CHILDREN YOU WILL BECOME THE HUNTED'

Williams has been arrested at least 10 times in Florida for assault, battery, domestic violence, unlawful possession of a weapon and other offenses. 

His most recent prior arrest came in 2016, when he was charged with aggravated assault for an alleged strangulation in Fulton County, Georgia. 

Homicide of Houston police officer William "Bill" Jeffrey

William "Bill" Jeffrey, a Houston police officer

William "Bill" Jeffrey, 54, a Houston police officer, was killed Monday while serving a felony warrant, authorities said.  (Houston Police Department)

Houston Police Department officers assigned to the Major Offenders Division were attempting to serve a narcotics-related warrant at a home on Sept. 20 when officer William "Bill" Jeffrey was fatally shot by 30-year-old Deon Ledet, according to police. 

Officers knocked on the door and asked to speak with Ledet, at which point the suspect came out and immediately opened fire on police, killing Jeffrey and critically wounding a second officer, Sgt. Michael Vance. 

Ledet was also killed in the ensuing gunfight with police. 

HOUSTON VETERAN POLICE OFFICER KILLED, SECOND WOUNDED WHILE SERVING NARCOTICS WARRANT, CHIEF SAYS

The 30-year-old had an extensive criminal history, including 18 arrests for felony drug charges, burglary, evading arrest, aggravated assault with a deadly weapon and other offenses. 

Deon Ledet shot and killed Houston police officer William "Bill" Jeffrey

Deon Ledet, 30, shot and killed Houston police officer William "Bill" Jeffrey in September, according to police.  (Houston Police Department)

The Harris County District Attorney’s Office requested a hearing on Nov. 17, 2020, to deny bail for Ledet on two recent drug charges given his habitual offender status, but District Court Judge Greg Glass granted Ledet a $20,000 bond, which he eventually posted. 

"The community is becoming more and more outraged," Houston Police Officers' Union President Douglas Griffith told Fox News Digital in September. "This is the 138th person, one of our officers, over the last two years, that has been killed by someone out on multiple felony bonds."

Shoot-out between criminal and Brevard County Sheriff's deputies

Brevard County Sheriff’s deputies got into a shoot-out in August with a man that Sheriff Wayne Ivey called a "violent career criminal"

Brevard County Sheriff’s deputies got into a shoot-out in August with a man that Sheriff Wayne Ivey called a "violent career criminal." (Brevard County Sheriff's Office)

Brevard County Sheriff’s deputies Brian Potters and Tyler Thoman pulled over a driver on Aug. 30 and were ambushed by an occupant of the vehicle, Paris Wilder, a 38-year-old man who Sheriff Wayne Ivey called a "violent career criminal."

More than 60 rounds were fired during the shootout, which left Wilder dead and Potters with multiple injuries. 

Wilder was out on bond for drug trafficking at the time and had a lengthy rap sheet, including at least 40 charges for attempted first-degree felony murder, aggravated assault while discharging a firearm, battery on a law enforcement officer and other offenses. 

"This case is a perfect example of what is wrong with our criminal justice system," Sheriff Ivey said in September. "When a registered career criminal with 23 felony charges, 17 misdemeanor charges, multiple convictions for violent offenses and two active and pending drug trafficking cases is out on our streets where he can attempt to kill our deputies and put other lives at risk, something is wrong with our system."

Homicide of Temple University student Samuel Collington

Latif Williams was sought for murder in the death of Samuel Collington

Latif Williams, left, was sought for murder in the death of Samuel Collington, right.  (Philadelphia Police Department/Family Handout)

Latif Williams, 17, was arrested earlier this year for allegedly carjacking a victim at gunpoint in Philadelphia, but was later released from jail after prosecutors withdrew the case because a key witness failed to testify. 

On Wednesday, Williams turned himself in to police following the Sunday killing of 21-year-old Temple University student Samuel Collington. 

MICHIGAN SUSPECT OPENS FIRE ON BUS, WOUNDING 3; LATER KILLED BY POLICE

Collington was found by officers with gunshot wounds to his chest and back after police received a 911 call about a man with a gun on the city's north side.  

Before he was released, Williams was facing charges of assault, robbery, possession of a firearm by a minor and other offenses stemming from the July incident, according to FOX 29 Philadelphia

Beverly Hills homicide of Jacqueline Avant

Jacqueline Avant

Jacqueline Avant, left, and Clarence Avant appear at the 11th Annual AAFCA Awards in Los Angeles on Jan. 22, 2020. She was fatally shot early Wednesday in Beverly Hills, Calif. 

Aariel Maynor, 29, was out on parole with multiple prior robbery convictions when he allegedly shot and killed 81-year-old Jacqueline Avant in her Beverly Hills home on Wednesday. 

About an hour after Avant was shot, Maynor apparently shot himself in the foot in the backyard of another home, authorities said. Los Angeles police officers in the department's Hollywood Division responded and took Maynor into custody. 

Surveillance and city cameras captured him traveling away from Avant's home, according to police. 

Aariel Mayor

Aariel Mayor, 29, was released on parole in September and had convictions for robbery and grand theft.  (California Department of Corrections and Rehabilitation)

Maynor was sentenced to five years in prison on Nov. 14, 2013, for second-degree robbery and inflicting great bodily injury. He was sentenced again in 2018 to a four-year prison sentence for second-degree robbery with enhancements for a prior felony conviction but was released in September of this year. 

CLICK HERE TO GET THE FOX NEWS APP

Jacqueline Avant was the wife of 90-year-old Clarence Avant, who was recently inducted into the Rock & Roll Hall of Fame and was known as the "Godfather of Black Music."

Fox News' Michael Ruiz, Danielle Wallace, and Louis Casiano contributed to this report.