Detectives investigating the death of a baby in a house fire arrested his mother on suspicion of murder, it was reported today.

Alexander Gallon, aged four months, was killed in the blaze at the two-bedroom property in Cowgate, Newcastle, on Sunday night.

The Evening Chronicle in Newcastle reported that his mother, Danielle Wails, 21, had been arrested.

Northumbria Police said a 21-year-old Newcastle woman was being questioned on suspicion of murder but refused to give any more details.

Another woman, in her early 20s, was released on police bail after being questioned as part of the inquiry. Ms Wails told police two men burst into her house, attacked her and tied her up, then fled after setting fire to the living room where the baby had been asleep.

Police, who appealed for help in tracing the attackers at a news conference yesterday, said they have found CCTV images of two men in the area shortly before the fire broke out.

A force spokeswoman said today: ''We have CCTV footage that shows two men at the corner of Link Road and Whitehorn Crescent at 10.30pm on Sunday.

''We would ask for these two men to come forward and contact the incident room.''

Early indications from a post mortem showed Alexander died as a result of the fire, police said.

Further tests will be carried out by Home Office pathologist Dr James Sunter and paediatric pathologist Dr Chris Wright.

Police said Ms Wails told them she was knocked out by the attackers and regained consciousness to find the house was on fire. She said she could not get to her baby because of the intensity of the heat.

She said she had been tied up with telephone cord and had dialled 999 using her tongue.

Neighbours were alerted but could not break the front door down, and when a fire crew managed to get through, she spilled out with her baby trapped inside.

When firefighters found Alexander on the floor of the property, he had already suffered serious injuries and he died at Newcastle General Hospital.

Detective Superintendent Barbara Franklin told a news conference yesterday: ''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.''

Ms Wails was released from hospital having suffered minor bruises to the face and was being comforted by her family yesterday.

Alexander's father Robert Gallon, also 21, was said to be distraught. He had regular contact with his son, although he did not live with Ms Wails.

Mother and baby had lived at the house in Link Road for just two weeks. It was leased by the Catholic charity St Cuthbert's Care, which helps young single mothers with their parenting skills.