Police are probing whether market massacre suspect Anis Amri was responsible for the murder of a young German boy in Hamburg two months ago.

The news comes as it also emerged that Amri was previously jailed for hijacking a vehicle in his home country of Tunisia.

Islamic State claimed responsibility for the October 16 knife attack which claimed the life of a 16-year-old called Victor E.

Murder squad detectives are probing the similarities between Amri and the photofit picture issued following the murder of 16-year-old Victor E.

Islamic State claimed responsibility for the October 16 knife attack which claimed the life of a Victor

A tribute to Victor on a banner reads: 'Our beloved friend, we think of you and miss you' next to river where he was stabbed

ISIS claimed responsibility for the fatal stabbing of a 16-year-old boy beneath Kennedy Bridge in Hamburg

A sign reading, 'Victor - we miss you', placed at the site of the stabbing in Hamburg

ISIS news agency Amaq stated: 'A soldier of the Islamic State stabbed two individuals in Hamburg on the 16th of this month. He carried out the operation in response to calls to target the citizens of coalition countries.'

Victor's girlfriend, aged 15, was with him at the time and not stabbed but pushed into the waters of the Outer Alster Lake.

When she made it to dry land she called the emergency services but her boyfriend died shortly afterwards in hospital. She is currently under psychiatric care.

If the group was responsible it would be its first lethal attack on German soil. An Afghan refugee who pledged allegiance to Isis attacked people with an axe on a train in July and was killed by police but his victims survived.

Radicalised: After reportedly being brainwashed by extremists while sleeping rough on the streets in Italy, Amri arrived in southern Germany in July 2015 - 18 months before Monday's tragedy pictured

Suspect: German police suspect that Amri drove this truck into terrified crowds at the Christmas market. They are in a desperate race to detain him and have described him as being probably armed and 'highly dangerous' before any further terrorist attack

Wanted: Having served four years in jail in Palermo, which also housed mafia bosses and gangsters, career criminal Amri, pictured, was freed four months early in May 2015

And an Isis suicide bomber a week later killed himself with a DIY bomb outside a cafe in Ansbach, injuring 19 people with no fatalities.

Hamburg police said they are looking for a man of 'southern' appearance, estimated to be about 23 to 25 years old and about 1.80 to 1.90 meters tall. He has stubble and short, dark hair.

Murder squad detectives are probing the similarities between Amri and the photofit picture issued for Victor's killer at the time.

'This is another lead we are following,' said a police spokesman.

Police are carrying out further searches in Berlin after Amri was apparently spotted at a city mosque after Monday's attack.

Amri suspect offered himself up as an ISIS suicide bomber and took a sinister video of himself walking the streets of the German capital

And he had previously been sentenced jailed for hijacking a vehicle, it has emerged.

Amri was jailed by a court in Kairouan, in northern Tunisia, in 2010 for stealing a truck, according to German newspaper die Welt.

But he fled his home country for Europe the following year to avoid being sent to prison for other robbery and violence offences.

Amri was sentenced to five years behind bars in 2011 - but left the country before and arrived illegally in Italy in early 2012 as a fugitive from justice.

His father, Mustapha, said he was later jailed for arson in Italy when he burned down a migrant reception centre during a violent protest on the island of Lampedusa - the entry point into Europe for hundreds of thousands of migrants fleeing north Africa and the Middle East.

Amri was one of a number of migrants who set fire to their mattresses, which burned the migrant centre holding 1,200 refugees to the ground.

Many refugees were given permission to travel freely through Europe but Amri was ordered to stay in the overcrowded camp because he claimed to be an unaccompanied minor.

Blaze: It is alleged that Amri became radicalised while sleeping rough in Italy after he was released from jail in Palermo following his sentence for arson on Lampedusa in early 2011

Burnt out shell: Amri was convicted of arson shortly after arriving in Italy for after a blaze on this migrant centre in Lampedusa, pictured, in September 2011

Jail term: Amri fled Tunisia where he was facing a five year jail term for robbery. After his release from prison for his part in the migrant riots on Lampedusa in 2011, security sources in in Tunisia say he was radicalised by ISIS fanatics while he was sleeping rough in Italy

Amri was one of a number of migrants who set fire to their mattresses, which burned the migrant centre holding 1,200 refugees to the ground

The fire, which destroyed three buildings, was reported to have been started by Tunisians, including Amri, who were told to go home after some were ordered to return to Tunisia.

Amri was released four months early from his four year sentence, arriving in Germany in July 2015 where he remained under the surveillance of the intelligence services for several months.

He had been arrested three times this year and his asylum application was rejected, but deportation papers were never served and he disappeared.

The Tunisian radical was known to be a supporter of Islamic State and to have received weapons training. He tried to recruit an accomplice for a terror plot - which the authorities knew about - but still remained at large.

He was under investigation for planning a 'serious act of violence against the state' and counter-terrorism officials had exchanged information about him last month.

With nowhere to go after his release, ISIS recruiters offered him protection before convincing him to sneak into Germany as a Syrian refugee, a source within Tunisia's anti-terror police revealed.

The source told MailOnline: 'Whatever he decided to do in Germany was started while he was in Italy.

His brother Walid (second from left, being interviewed) posted a photo of him on Facebook following the identification of Anis as the prime suspect

'They gave him food and shelter and persuaded him to carry out a mission for them. It was in Italy that he was radicalised.

'He entered Germany posing as a Syrian refugee. He was a vulnerable young man and they showed kindness to him.'

But the terror he brought to the streets of the German capital is a far cry from a youngster who loved amateur dramatics and cookery, his sister told.

Older sibling Najoua said: 'He did drink, but moderately, he took cooking and acting classes when he was in Italy, he liked his life before he was jailed [in that country].

She added: 'When he was a child in school I was university studying literature, he used to come to me and ask me to read him pre-Islamic poetry and explain to him what it meant. He really appreciated its beauty and he was passionate about it.'

His brother Walid posted a photo of him on Facebook following the identification of Anis as the prime suspect.