A WISCONSIN MAN has been convicted of killing six people and injuring dozens of others when he drove his SUV through a Christmas parade last year, ending a trial in which he defended himself erratically and sometimes confrontationally.

It took the jury a little over three hours to find Darrell Brooks guilty of all 76 charges, including six counts of first-degree intentional homicide.

He faces a mandatory life sentence on each homicide count.

Brooks, wearing a suit and tie, quietly leaned his bowed head on folded hands as the verdicts were read.

His demeanour was a stark departure from previous days of the trial, when his sometimes-outrageous behaviour drew rebukes from the judge.

Brooks drove his Ford Escape into the Christmas parade in Waukesha in suburban Milwaukee on 21 November, moments after fleeing a domestic disturbance with his ex-girlfriend, prosecutors said.

Six people were killed, including eight-year-old Jackson Sparks, who was marching in the parade with his baseball team, and three members of the Dancing Grannies, a group of grandmothers that dances in parades.

Dozens of other people were hurt, some severely.

The incident deeply scarred the community of 70,000 people about 16 miles west of Milwaukee.

Community members built memorials to the dead and held vigils.

The anger was still evident on Wednesday; someone in the gallery shouted “burn in hell” as the verdicts were read.

Brooks pleaded not guilty by reason of mental disease this year but withdrew the plea before his trial began with no explanation.

Days before the trial started, he dismissed his public defenders, electing to represent himself.

District attorney Susan Opper called to the stand police officers and paradegoers who testified they saw Brooks behind the wheel of the SUV.

Brooks struggled to mount a defence, launching into meandering cross-examinations, refusing to recognise his own name or the court’s jurisdiction over him and muttering under his breath that the trial was not fair.

He got into such intense arguments with Judge Jennifer Dorow that several times during the lead-up to jury selection she moved him into another courtroom where he could watch the proceedings via video and she could mute his microphone when he became disruptive.

One day after he was removed to the other courtroom, he stripped off his shirt and sat bare-chested on the defence table with his back to the camera.

On another day, he built a barricade out of his boxes of legal documents and hid behind it.

He also tossed his copy of the jury instructions into the bin.

Opper told jurors during her closing arguments that Brooks’ refusal to stop once he entered the parade route shows he intended kill people.

Judge Dorow allowed Brooks back into the main courtroom to deliver his closing speech to jurors face to face.

In a rambling, repetitive speech, he tried to raise doubts about whether the SUV’s throttle malfunctioned and whether the driver simply panicked.

He lamented how he has not been able to see his children since he was arrested and insisted he is not a murderer.

Opper countered during her rebuttal that a Wisconsin State Patrol vehicle inspector testified earlier that the SUV was in good working order.

She warned jurors that Brooks was just trying to play on their sympathy.