A video has been posted online showing British man Abdul Waheed Majid, who is thought to have carried out a suicide bombing in Syria, the BBC's security correspondent Frank Gardner has said.
The 41-year-old, from Crawley, West Sussex, is believed to have bombed a jail in Aleppo on 6 February.
The footage shows Majid next to a large armoured truck bomb that was driven into the walls of the prison.
His family said they believed he was in Syria for humanitarian purposes.
Anti-terror police searched Majid's house in Langley Green on Wednesday.
Officials have not confirmed his identity citing a lack of DNA evidence, although community sources in Crawley have confirmed to Mr Gardner that Majid is the man in the video.
Mr Gardner said: "The 43-minute video clearly shows Mr Majid from Crawley in Sussex, dressed in white next to the large armoured truck bomb, which he is believed to have driven into the walls of Aleppo prison on 6 February."
'Second house raided'
Majid is believed to have been responsible for the prison attack that resulted in inmates escaping.
The bombing, in the north of Syria, is thought to have been the first carried out in the country by a Briton.
People living near Majid's home told the BBC he left some weeks ago for Syria.
An al-Qaeda-linked rebel group, the al-Nusra Front, had named Majid by an alias - Abu Suleiman al-Britani.
Counter-terrorism police raided a second house in Crawley on Thursday, which was believed to have been occupied by one of Majid's close friends.
That house is also the former home of schoolgirl Sarah Payne's killer Roy Whiting, according to neighbours.
The South East Counter Terrorism Unit said there had been no arrests following the searches in Crawley.
The Manchester home of student Abu Layth has also been searched by police. He is believed to have been killed while fighting in Syria.
Inquiries are continuing into how Layth, whose family name is Khalid Raoufi, died. Greater Manchester Police have confirmed his family is not under investigation.