A homeless man suffered second-degree burns after thugs set his tent on fire.
The victim, in his 40s, was sleeping in Canterbury, Kent, on Wednesday afternoon when he was attacked.
He suffered burn injuries to his torso during the horrific incident, which occurred behind Kingsmead Leisure Centre.
The man's parents were made aware of the incident and said they were horrified. But, they said they felt "helpless" as they live abroad in Cyprus.
His father told Kent Online : "It's truly shocking, and we have urged him to get treatment as soon as possible.
"It's alarming that someone would do something like that to another person who is clearly already vulnerable.
"We did see him recently when we came back to Canterbury, but obviously feel a bit helpless to support him now we are now so far away."
Police and paramedics attended the scene, but originally the victim declined to make an official complaint.
However, police officers have now launched an investigation after talking to the victim for a second time.
A police spokesman said: "At around 4.30pm on Monday, August 15, police were was called to an area of grassland behind the leisure centre in Kingsmead Road following concern for the man, whose clothes were seen alight."
The man is reportedly known to homelessness charity Catching Lives.
Emma McCrudden, Interim manager at the charity, said the homeless community often face abuse and attacks on the street.
"I can't talk about this particular incident because I haven't spoken to the person involved about it, but it is not unusual for rough sleepers to have their tents set alight, suffer assaults, have their possessions stolen and even be urinated on."
