A HEAVILY pregnant mother was last night fighting for her life - and the life of her unborn child - after an arson attack at her home in which her only son died.

Medical staff were last night battling to save the life of 29-year-old Janine Dodd, left in a critical condition after she leapt from an upstairs window to escape the ferocious heat and flames.

Her son, 11-year-old Dean Pike, was trapped inside the burning building and firefighters later found his body on a landing.

In his desperate attempts to escape the fire, which broke out as he slept, Dean managed to get out of his room - but found his only exit blocked after the intense fire burnt away the stairs.

Detectives yesterday laun-ched a murder investigation after sniffer dogs discovered traces of accelerant at the front door of the privately-rented house in Mordey Close, in the Hendon area of Sunderland.

Detective Superintendent Barbara Franklin, who is leading the inquiry, said: "This is an horrendous incident which has shocked both the community and the inquiry team. We find it hard to believe that someone could do this to an 11-year-old boy and his mother.

"There is no question that it was done deliberately and this is a murder investigation."

The fire broke out shortly before 1am and, fuelled by the accelerant, swept through the end-of-terrace house.

Neighbours battled to get into the house but were forced back by the heat, which was so intense the windows exploded.

Miss Dodd, who jumped from a first-floor window into the back garden, was given first aid at the scene, then taken to the intensive care unit at Newcastle General Hospital.

She is suffering from severe burns, the effects of smoke inhalation and a serious head injury, which police believe was caused as she escaped.

Doctors are hopeful they can save her unborn baby, due at the end of summer, which is thought to have been unharmed.

A spokesman for the Tyne and Wear Fire Service said: "The house was completely destroyed in the fire and the staircase was so badly burnt out it couldn't be used by crews."

Dean, a pupil at nearby Southmoor School, was taken to Sunderland Royal Hospital but was pronounced dead on arrival.

Headteacher Elizabeth Bowman said pupils were distraught by the death of the popular pupil, who was a keen footballer and singer and had just completed his first year at the school after previously having attended Valley Road Primary School.

She said: "Dean was a lovely young man, he was a lively, enthusiastic, he was very popular and a pleasure to have in the school. He was a real character.

"The children have been talking today about what they liked best about him and my favourite was 'a small boy with a big heart'.

"We are devastated. The children are obviously very, very saddened and shocked and, I have to say, frightened."

The school organised bereavement counselling for 200 of Dean's friends yesterday.

The sense of shock extended into the rest of the community. A friend and neighbour of Miss Dodd, who did not wish to be named, said: "I can't understand why anybody would dream of hurting her, she's a lovely girl.

"She loved Dean so much, he was everything to her and a smashing little lad. It is heartbreaking to think he died in such an awful way."

Dean's father, whose relationship with Miss Dodd ended several years ago, was yesterday helping police build up a picture of her lifestyle.

The family had only moved into the house about six weeks ago, having previously lived with Miss Dodd's aunt nearby.

Police said that the house had been empty for the previous year, and there was no obvious motive for the attack.

The area has not seen any other arson incidents recently and officers are not linking the tragedy to any other investigation.

Chief Superintendent Jim Campbell, area commander for Sunderland, appealed to the community to come forward with information on the killing.

He said: "People have got to have morals out there and have got to want to do something about this."

A police incident room has been set up at Southwick Police Station, Sunderland, and can be contacted on 0191-454 7555 ext 66718.