John Kafunda and Reece Donovan face lengthy sentences after conviction for robbing Ashraf Rossli while pretending to help him

Two men who pretended to be good Samaritans then robbed a student whose jaw had just been broken during last year's riots in London face lengthy jail sentences after being convicted by a jury.

Mobile phone footage showing Ashraf Rossli, 21, from Malaysia, lying injured before being helped to his feet then robbed by the two who stole items from his bag, caused widespread outrage when broadcast on YouTube.

John Kafunda, 22, of Ilford, and Reece Donovan, also 22, of Romford, were found guilty of robbery and violent disorder at Wood Green crown court in north London. The judge warned they could expect lengthy custodial sentences when they are sentenced on 13 March.

Rossli, an accountancy student who had been in Britain for a month, was attacked on his way to keep a frightened female friend company on 8 August as he tried to cycle through a crowd on a flyover in Barking, east London.

His bicycle was stolen and he was punched, breaking his jaw in two places. Beau Isagba, 17, was convicted of assaulting him and stealing his bike in a separate trial and will be sentenced on 9 March. The assault left Rossli bleeding on the pavement, and he now has metal plates in his jaw.

Minutes later Kafunda was captured on camera putting his arm around a dazed Rossli and pretending to help him, while Donovan rifled through the student's bag. In a police statement Rossli, who is 5ft 4ins and of slim build, said a portable Sony PlayStation and 10 games were taken, worth ?500.

He said in his statement: "I was sat on the pavement with blood pouring from my mouth. I remember being approached by a male who asked if I was OK. I remember being pulled to my feet, then I felt someone again tugging at my rucksack.

"I was not in a position to defend myself and was still suffering from the effects of being hit. I knew they were stealing from me, but I could do nothing. Once they had taken what they wanted, they left."

As the jury unanimously convicted both men of robbery and violent disorder, Kafuna said: "You're sending an innocent man down, bruv, innit." Donovan was also convicted of theft and of later burgling a Tesco store.

Detective Sergeant John Healy, of the Metropolitan police, said: "At the time of this incident, Mr Rossli was suffering the effects of a broken jaw and he was unable to defend himself. Kafunda and Donovan took advantage of him posing as good Samaritans to steal his property".

Chief Superintendent Gary Buttercase, temporary police borough commander at Barking and Dageham, described Rossli, from Kuala Lumpur, as "a man of humility and dignity", adding: "I am particularly pleased we have managed to get justice for the appalling attack he suffered and the subsequent theft that has attracted derision from across the world." Jenny Hopkins, from the Crown Prosecution Service, said: "The image of Reece Donovan rifling through the contents of this vulnerable young man's bag was one of the most shocking images from the public disorder in the summer of 2011."

After the attack and robbery Rossli said he was determined to continue his studies in Britain despite his ordeal, telling a press conference: "Britain is great. Before I came here I was eager and I haven't got any ill feelings about what happened. I feel very sorry for the people that did this." A fund was set up to help him.

Following Friday's verdicts, a spokeswoman said: "He is grateful for the work the police have done in bringing the case and also for the support of the British public for what they have done for him."

Both defendants had denied the charges. Donovan, a mechanic, claimed he was in the area to buy skunk cannabis, but had originally told police he was at his mother's house in Limehouse, east London, because he feared being questioned about the drugs. Cell site mobile evidence had proved he was in Barking when the attack and robbery took place. Kafunda claimed he was at a neighbour's house on the night of the riots. The two had claimed they had not seen each other for three weeks at the time of the riots because Kafunda owed Donovan money for fixing his motorbike.