A 70-year-old man who was set alight in Birmingham has been named as Mohammed Rayaz.
He was attacked as he walked back from a mosque on Monday night and has "horrific injuries".
Video showed him being approached and speaking with a man before being sprayed with an unknown substance and set alight.
A man arrested on suspicion of his attempted murder has now been arrested over a similar incident in west London last month.
Police said the pair spoke for about five minutes before he was doused with fluid and set alight. He was taken to hospital with severe burns to his face and arms.
A man was arrested on Tuesday afternoon in connection with the Birmingham attack and on Wednesday he was also arrested over the London incident.
He remains in custody on suspicion of two counts of attempted murder.
Mr Rayaz was attacked on Shenstone Road in Edgbaston as he walked back from Dudley Road mosque shortly after 7pm.
West Midlands Police said they would not speculate about potential motives and urged anyone with CCTV, doorbell footage or other video to get in touch.
A friend of Mr Rayaz said he'd been left with life-changing injuries.
"He has serious injuries to the upper part of the body and also his hands and his face at the moment," explained family spokesperson Shahbon Hussain.
"He's not even able to open his eyes, he's undergoing various skin grafts as well as a result of the horrific injuries."
Mohammed Abbkr, 28, has been charged with two counts of attempted murder after two men were set alight in Birmingham and London after leaving mosques, West Midlands Police said.
West Midlands Police said Abbkr is alleged to have sprayed a substance on two men and set it alight in separate attacks, in Ealing on 27 February and Birmingham on 20 March.
The Metropolitan Police said an incident in Edgbaston, Birmingham, in which a man was set alight on his way home from a mosque on Monday has been linked to a similar incident in Ealing, west London, where another man was set on fire in February.
Detectives from the Met’s West Area Command are working with West Midlands Police to establish the full circumstances surrounding the incidents, with the West Midlands force is leading the investigation.
One of the victims, a 70-year-old man, was set alight just yards from his house as he walked home from a Birmingham mosque.
His son pleaded for help saying “my dad is on fire”, the family’s lawyer has said.
The incident left Mohammed Rayaz, a retired factory worker, with severe burns to his face, hands and chest.
He remains in stable condition in Birmingham’s Queen Elizabeth Hospital after events unfolded just around the corner from his home in Shenstone Road, Edgbaston, Birmingham, at about 7pm on Monday.
Family friend and lawyer Shahbon Hussain, whose office is opposite the mosque, said he got a text message from Mr Rayaz’s son within minutes of the attack.
He said: “I got a text message saying, ‘my dad is on fire – somebody has lit my dad on fire’.
“I thought I had misread and that maybe someone had set his car on fire but it became obvious I hadn’t misread at all.
“He heard his dad screaming, the family had gone out the house and seen him on fire.
“I immediately went over and the police, ambulance and fire brigade were already there.”
Mr Rayaz was said to be walking home from the mosque around 6pm on Monday when the suspect began speaking with him. The conversation then became intense and the pensioner was reportedly doused in a liquid before being set on fire.
Mr Hussain, who also chairs the local Streetwatch group, said: “He was taken to hospital and, in the meantime, I started detective work, putting every clue we had onto the community’s WhatsApp group, which is 160 people and managed to collate all CCTV and Ring doorbell footage.
“All that was passed to the counter-terrorism unit officers.”
He added there was a community meeting between police and locals on the Tuesday morning and, after it had ended, Mr Hussain got another call to say a man matching the description of a suspect was at Dudley Road mosque.
Abbkr will appear at Birmingham Magistrates Court on Thursday. By Thomas Kingsley, Sky News/Yahoo News
