A woman has been arrested and bailed by police investigating the death of a baby boy in a fire on Tyneside.
Four-month-old Alexander Gallon died in the fire
Four-month-old Alexander Gallon died in the fire at a house in Cowgate, Newcastle, on Sunday night.
The baby's mother Danielle Wails, 21, was bound with a telephone cord by two men who entered the property, attacked her and set the house on fire.
Police said that the attackers would have been aware that the baby was in the house.
A police spokeswoman told BBC News that the arrested woman, in her early 20s, was not the baby's mother.
She added that officers were still actively hunting the two men.
The mother and her baby had been at home alone on Sunday, with the front door left open.
Officers said Ms Wails was in the kitchen at about 2230 BST when two men wearing black came in and punched and kicked her.
It is believed she passed out after falling to the ground and was dragged to the living room where her son was sleeping on the sofa.
When Ms Wails regained consciousness the room was filling with smoke and she was tied up, police said.
She managed to dial 999 with her tongue and scream for help through the letterbox.
Fire crews rescued Ms Wails and her son. They were taken to Newcastle General Hospital but Alexander was pronounced dead.
Det Supt Barbara Franklin called the arsonists "wicked".
She said: "The baby was crying, he was in the same room as the mother, and it is a tiny living room. They could not have not known the baby was in the house.
"It is difficult to comprehend the wickedness of someone who could do such a thing and we appeal for the public to come forward and help us.
"This is a horrific incident which has left a baby dead and a young mum injured."
A post-mortem examination is due to be carried out on the baby on Tuesday.
The baby's father, Robert Gallon, 21, did not live with Ms Wails, but played an active part in his son's life. Police said he was distraught.
Footage from a CCTV camera in the area is being examined.