A woman has been arrested after a 10-year-old boy was killed in a dog attack.
The 28-year-old, from Caerphilly, was questioned on suspicion of being in charge of a dog dangerously out of control, causing injury resulting in death. She has been released on bail.
Jack Lis died at the scene of Monday’s attack at Pentwyn, Penyrheol.
Meanwhile, a man who tried to pull the dog off Jack said he wished he could have done more to save him.
“That will be with me for the rest of my life,” said Kirk Wiegold.
“My thoughts and love are with the young boy, Jack’s family, at this sad time.
“I wish I could have done more than I did to help the young boy… but there was nothing I could do.”
Two men who volunteered to be spoken to by police in relation to the same offence as the woman were also later released.
They were a 34-year-old from Mountain Ash, Rhondda Cynon Taf, and a 19-year-old from Caerphilly.
Jack and his friend were alone when the attack happened.
The 10-year-old’s friend sought the help of Mr Wiegold, who lives several doors down on the same street, but he was unable to stop the dog.
Gwent Police said work was continuing to identify the breed of the dog, which people locally have claimed was a type of American pit bull.
Caerphilly MP Wayne David said it was a “terrible, horrible incident which should never have happened”.
He said there should be a review of the Dangerous Dogs Act as a “matter of urgency”.
“We need to have in place more protection for members of the public and that requires the legislation to be revisited, but it needs to be done quickly and speedily,” he added.
“What has happened in Caerphilly has to be put in a broader context. There have been a number of incidents around the country.”
Ch Supt Mark Hobrough said: “As we’ve arrested an individual on suspicion of an offence linked to the attack, and spoken to two others voluntarily, we’re looking to identify where any criminal matters have occurred.”
He also urged people to consider the “tone and language” used in social media comments about the identities of anyone that could be involved.
“As this is a live investigation such comments may have an impact on our ability to bring anyone found to have committed a criminal offence to justice,” he added.
Jack was a pupil at Cwm Ifor Primary School in Caerphilly, whose head teacher, Gareth Rees, said the whole school community had been “rocked by the tragic events”.
His mother Emma Whitfield also paid tribute to her “beautiful” and “sweet” son.