An online petition to overturn the verdicts in the killing of PC Andrew Harper has more than 200,000 signatures.
Last Friday, three teenagers were convicted of the police officer’s manslaughter but cleared of murder.
Newlywed PC Harper, 28, died from catastrophic injuries when he was dragged for more than a mile behind their Seat Toledo car after his ankle was caught in a strap behind the vehicle as he tried to apprehend them.
The driver, Henry Long, 19, and passengers Albert Bowers and Jessie Cole, both 18, were trying to escape capture at Sulhamstead, Berkshire, after stealing a quad bike on 15 August last year.
The men had been seen laughing both inside and outside of court during their trial at the Old Bailey. They hugged each other when the manslaughter verdicts were handed down.
More than 200,000 people have signed a Change.org petition calling for the manslaughter verdicts to be overturned.
One of the signatures appears to be from PC Harper’s mother, Debbie Adlam.
She wrote: “Andrew James Harper is my son. I am disgusted that he has been let down.
“Utterly and bitterly disgusted with the outcome. Andrew went to work to serve us all. And this is how he was repaid.”
The police officer’s widow, Lissie Harper, said she was “immensely disappointed” the three teenagers were cleared of murder.
Following the verdicts, she said: "This crime, whatever the outcome deliberated over in court, was brutal and senseless.
"The way in which Andrew was robbed of his life we all know to be barbaric and inexplicable.”
At the weekend, she shared an emotional letter on Facebook on what should have been the couple’s first anniversary together.
In the post, she said their first anniversary “should have been wildly different, instead of celebrating with you on our first anniversary, I am alone in utter disbelief”.
“I feel as though I have lost a limb, except it’s so much worse than that, because actually I’ve lost the best part of myself.”
The teenagers admitted plotting the theft and Long pleaded guilty to manslaughter but each denied knowing that PC Harper was there.
Their defence claimed the incident was a "freak event" that none of them could have planned or foreseen.
But the prosecution said at more than 6ft and weighing 14 stone, the defendants must have been aware PC Harper was being dragged to his death.
A jury deliberated for more than 12 hours to clear all three of murder but convict Cole and Bowers of manslaughter.
Following the verdicts, it can now be reported that Long had previously threatened to "ram" a police officer as he chatted with a police community support officer.
In the conversation in July 2018, ruled inadmissible during the trial, Long said: "You can't touch me now 'cos I've passed my driving test and if police try to stop me I will ram them."
Long had previous convictions for battery, being drunk and disorderly and shoplifting.
Bowers also had youth convictions including for battery, criminal damage, sexual assault, and having an offensive weapon.
All three defendants were said to be members of the travellers' community.
Judge Mr Justice Edis had also ordered extra security measures amid fears of potential juror intimidation by supporters of the defendants, it can now be reported.
Thames Valley Police Detective Superintendent Stuart Blaik said: "Long, Bowers and Cole have shown no remorse for what happened that evening at any stage."
The trio are due to be sentenced on Friday.