London (CNN)UK police have arrested three more men in connection with a suspected acid attack on a three-year-old boy in the city of Worcester.
'Acid attack' on toddler: Three more suspects arrested
The suspects, aged 22, 25 and 26, were detained in London on suspicion of conspiracy to commit grievous bodily harm, West Mercia Police said.
The toddler suffered serious burns to his face and an arm as he sat in a pushchair in the Home Bargains store in Tallow Hill mall on Saturday afternoon.
A 39-year-old man was arrested in another English city, Wolverhampton, on Sunday, police said.
The child was treated in the hospital before being released Sunday afternoon. Police said the long-term implications of his injuries were unknown as of Monday morning.
Police yesterday issued a public appeal, releasing CCTV images of three men who were seen around the child at the time of the incident.
"The incident will rightly shock the local community and I would like to reassure local people that we are carrying out a thorough investigation to identify those responsible. At this time, the motive for the attack is unclear. Officers are working hard to establish exactly what happened and what the substance involved was," West Mercia Police Chief Superintendent Mark Travis said in a statement Sunday.
The member of Parliament for Worcester, Robin Walker, described the incident as "horrific."
"The shock will be universal, anyone conducting such an attack on a small child is just appalling," he told the UK Press Association on Sunday.
"It's an issue which rightly there has been a lot of concern in Parliament and a move to toughen sentences for any kind of acid attack."