Police have named a six-month-old baby boy thought to have been murdered by his father who then took his own life.
Ollie McBride was found in a "very poorly condition" at a house in Preston yesterday and was rushed to hospital where he was pronounced dead on arrival.
His father Paul McBride, 39, was found hanging at the address.
Detectives are awaiting post-mortem results on the youngster who had "no obvious signs of injury".
The boy's mother raised the alarm when the hackney cab driver failed to return him home as agreed.
Relatives of the couple - who had recently separated - called at the home of Mr McBride's mother in Marl Hill Crescent, Moor Nook, where they made the grim discovery.
It is known the pair had a recent history of domestic problems and police are understood to be looking at the theory that Mr McBride may have acted in revenge against his ex-partner.
Lancashire Police have launched a murder investigation but are not looking for anybody else in connection with the incident.
Detective Superintendent Neil Esseen, who is leading the investigation said: "There is a little bit of domestic history between the parents with some arguments.
"We are trying to find out what bearing that had on yesterday.
"Whether it is a revenge attack is too early to say, that would be speculation. We will be looking at all sorts of theories.
"The mother is obviously very distraught and she is being comforted by trained specialist officers.
"It is vitally important that we are able to tell the mother what has happened to her baby."
Mr Esseen said a post-mortem examination on the boy would take place later today.
"There was no obvious signs of injury to the child," he said.
He added that there had been contact with a number of agencies regarding the family.
It is believed Mr McBride and his ex-partner, aged in her mid-30s, had been living together in the Ribbleton area of the city until recently.
Mr McBride's mother, Denise Betts, was on holiday in France when the discovery was made shortly after 6pm yesterday and is now returning home.PA