A second arrest has been made over the death of a mother and her four-year-old son in a house fire.
A 23-year-old man from Eastbourne is being held on suspicion of two counts of murder and one of attempted murder.
He was arrested at an address in the town at around 1pm on Monday.
Another Eastbourne man, 47, has been released under investigation after he was arrested on Sunday on the same charges.
Police believe Gina Ingles, 34, and her son Milo Ingles, four, died in the blaze at their home in the seaside town in East Sussex, but they have not been formally identified.
The mother’s partner, Toby Jarrett, 26, remains in an induced coma having been taken to hospital in the early hours of Tuesday suffering from burns.
The family of Ms Ingles and Milo paid tributes to their “shining lights”, adding that he was “a beautiful little boy so full of fun and smiles” and she was “a kind and free-spirited person with a big heart”.
Firefighters were called shortly after 1am on Tuesday, but their bodies were only found in a first floor bedroom in Croxden Way at noon on Wednesday.
Post-mortem examinations showed they died from smoke inhalation, Sussex Police said.
Detective Chief Inspector Mike Ashcroft said: “We have arrested two men in connection with this horrific incident – one is now in custody being interviewed and the other has been released under investigation following questioning.
“However, the investigation is still in its infancy and we are continuing to appeal to anyone who has even the smallest piece of information which they think might help us to find out who is responsible for committing this terrible crime to get in touch with us.”