The father of the three-year-old boy doused in acid while shopping with his mother has been arrested and is being questioned over the attack.

The 39-year-old suspect, an Afghan asylum seeker who has not been named, was the first suspect detectives held after the boy was targeted while sitting in a pushchair during a shopping trip to Home Bargains with his mother.

Three other younger men are also being grilled in connection with Saturday afternoon's horrific attack in Worcester after they were arrested 130 miles away in Walthamstow.

They are reportedly eastern Europeans from the Romani community and accomplished bare-knuckle fighters, their east London neighbours said.

West Mercia Police believe the child was deliberately targeted in Home Bargains on Shrub Hill Retail Park at Tallow Hill. They have released images of three men (pictured) they would like to speak to

Today a fifth man, 41, from Wolverhampton, was arrested on suspicion of conspiracy to commit grievous bodily harm.

It is now thought the target might have been the boy’s mother.

The couple had initially settled in Wolverhampton after fleeing war-torn Afghanistan 11 years ago.

Last year she left her husband, a taxi driver, and moved to a house in Worcester with their three children, now aged ten, eight and three, to start a new life.

A neighbour recalled shouting matches between the couple, while another said when the woman left her husband broke down in tears claiming she would not let him see their children.

It is believed the thugs who carried out the acid attack on the boy had been monitoring the family after tracking them down to their new semi-detached home.

Detectives have been questioning residents about sightings of suspicious people and vehicles in the area.

When the pair were in a relationship she would wear a full veil but in recent years had removed it and moved to an address in Worcester 30 miles away with the children.

It is believed the estranged father discovered the whereabouts of his wife when a photo appeared in a local newspaper showing one of the children at a local event.

It is alleged that the gang bungled the attack and the three-year-old got splashed with the noxious substance accidentally in the process.

Police have now arrested four men - but none of them in Worcester. Three were in Walthamstow, London, last night and another in Wolverhampton

A West Mercia Police source confirmed to MailOnline that the older detainee is the victim's father from Wolverhampton.

She said today: 'He is still in custody. No charges as yet have been brought. This is an ongoing investigation.'

The man, who is understood to have split up from his partner and mother of his toddler son, is being held on suspicion of conspiracy to commit grievous bodily harm.

The mother had been hiding in a safe-house after a fractious break up.

Following the attack she and her son, who was treated in hospital for acid burns to his hands and face, were moved into a police safe house amid fears they could be attacked again.

Mark Travis, Chief Superintendent of West Mercia Police, hinted that a community dispute may have led to the vile attack

She had been living with the toddler and her two other children in a secluded residential street in Worcester after fleeing the family home in Wolverhampton because of 'difficulties within her relationship,' a new neighbour said.

Her child suffered serious burns when a bright pink acid was thrown over him as he sat in his pushchair in the city's Home Bargains store on Saturday while his mother shopped.

Four men have been arrested in connection with the attack - and she is now in a safe house with her son under police protection amid fears they could be attacked again.

One neighbour said there had been 'bad blood' caused by a family dispute and said the attack may have been launched over the end of a relationship with the three-year-old's mother, who could have been the true target.

A source close to the investigation revealed the mother, who has not been named, had fled to Worcester from Wolverhampton after 'difficulties within her family'.

A 39-year-old was later arrested in the city.

The source said: 'She had moved to Worcester from elsewhere but hasn't been here long. She had moved because of difficulties within her family.

'Nobody knows her really well and she didn't have any connection with Worcester. That's why she was moved here, because she was fleeing her previous situation.

'Somehow the parties she was in a dispute with found out where she had moved to and that's how this horrendous incident has happened.

'The acid attack was targeted at her. The child just happened to get in the way.'

Chief Superintendent Mark Travis, who is leading the investigation, says he is keeping an 'open mind' about the motive and target of the attack.

But hinting about a row he said: 'This is not the way to resolve issues and disputes in communities'.

Chief Superintendent Mark Travis said: 'At this time we are treating this as a deliberate attack on a three-year-old boy.' Pictured: The men wish to speak to

The mother screamed 'What have you done to my baby?' after the thugs hurled the pink acid at the toddler in an attack which was captured on CCTV in the discount store.

Three men, aged 22, 25, and 26, were arrested in Walthamstow, east London in the early hours of yesterday morning on suspicion of conspiracy to commit grievous bodily harm.

Neighbours said they believed the attackers were from the 'gypsy community'.

On Sunday officers made enquiries near the woman's home, asking residents if they had seen any suspicious vehicles or people in the area.

And last night police forensic officers could be seen combing the area. They were also seen searching a nearby phone box.

Police have said they are keeping an 'open mind' about the attack but do not believe it was gang-related. They have ruled out racial tension or any link to the nearby English Defence League march.

Chief Superintendent Mark Travis added: 'Officers are working hard to establish exactly what happened and what the substance involved was.' Pictured: The store in Worcester

Police officers conducting a search of Shrub Hill Retail Park in Worcester on Sunday

Officers are investigating a suspected acid attack on a three-year-old child on Saturday

A neighbour said: 'Police asked us if we had noticed any strange vehicles or anything disturbing. At first we thought it might about a robbery but we were shocked to find out that it was connected to the horrible acid attack. We have not seen the woman for a few days.'

Neighbours said she did not appear to have a partner and had been seen taking her children to school each day.

A neighbour said: 'The house she was living in is a safe house. We have been told that someone was paid to attack the woman – but they missed and got the child.

'It's disgusting that men would do this.'

The woman and her children have since been moved to another safe house.

A 39-year-old man from Wolverhampton who was arrested on suspicion of conspiracy to commit grievous bodily harm remains in police custody.

The very thin blue line: he's made of paper Pictured: The cardboard PC The police officer looked a bit wooden, and as shoppers got closer, they could see why. This life-size cardboard policeman was spotted in the Worcester branch of Home Bargains yesterday. Flat-pack PCs are an increasingly popular way for cash-strapped forces to boost their street presence. They are often seen in petrol stations to deter motorists from driving away without paying and in shops to discourage shoplifting. Advertisement

Yesterday Nick Carson, from West Midlands Ambulance Service, who treated the little boy, told how the fluid had an acrid, chemical smell.

He said: 'It's horrific, absolutely horrific. We had no inkling or any reason to suspect it was an acid attack.

'We just thought that maybe he had come into contact with some sort of chemical. But to find out afterwards that that was the case, it's shocking.

'The fluid that I saw was pink in colour. It had quite a strong smell. No bleach or acidy type smell but it was an astringent kind of smell. Just smelt like a chemical really.'

Chief Superintendent Travis said the boy's relatives were coming to terms with the 'shocking' attack.

He told a press conference: 'It's a difficult time for them and we need to make sure that while we work through the investigation they are safe and secure and are allowed to deal with the issues that they face.

'I want to make sure the message is really clear that this is a very, very rare occurrence and what we will do is work to make people understand that this is not the way to resolve issues and disputes in communities.'

He added: 'The incident was captured on CCTV but we will not release any footage that showed the substance being thrown or sprayed.

'A number of other exhibits from the area have also been taken for examinations.

'We have looked at the movement of people in the footage throughout the area and consider this to be a deliberate act against the little boy.'