A man who took away the remains of a cat that "died from horrific burns" after it had fireworks strapped to its torso is being sought by police.
Mark Copeland said he discovered the fatally injured black cat in Thorndike Avenue, Derby, at midday on Saturday.
He said a man then arrived in an unmarked white van, claimed he worked for the RSPCA and drove off with the animal's corpse.
The RSPCA said no-one from the animal charity had attended the incident.
Derbyshire Police has appealed to trace the driver of the van, who did not leave his contact details.
Mr Copeland, 25, who lives in the Alvaston area and has four cats, said he was "shocked and sickened" when he found the "tortured" cat.
"The two rockets had been lit... I felt sick," he said.
"The cat's paw had been blown off and it only had a bit of black fur left on its tail, the rest was burnt.
"It was struggling to breathe from the horrific burns and then it just passed. I can't get the image out of my head."
He added the man claiming to be from the RSPCA told him the cat had a microchip and then took it away in his van.
Mr Copeland called his sister as he feared the cat may have belonged to her.
Sam Copeland-Whelan, 32, who reported the attack to the police, said she was "absolutely heartbroken" when her brother told her.
"The people who did this are disgusting and heartless... they've attacked an innocent and defenceless animal."
The RSPCA said: "We didn't attend the incident as we weren't contacted about it."
It added that it was "absolutely appalled" to hear about the "awful" attack and was liaising with the police.