A father is thought to have killed his six-month-old son before hanging himself.
Taxi driver Paul McBride, 39, was found dead at his mother’s house in Preston, following a search yesterday.
His son, who has not been named, was found in a “very poorly” condition” and taken to hospital where he was later pronounced dead.
Lancashire Police has launched a murder investigation but is not looking for anybody else in connection with the incident.
Officers and family had been looking for the father, described by neighbours as “jolly” and “jokey”, after concerns were raised about his welfare.
His sister found his body after arriving at their mother’s home (pictured) in Marl Hill Crescent, Ribbleton, shortly after 6pm.
Their mother, Denise Betts, is thought to be on holiday in France.
The baby’s mother, who was not married to Mr McBride, was being supported by trained police officers.
A post-mortem examination will take place today to establish how her little boy died.
A police spokeswoman said detectives from the force’s Major Investigation Team were leading the inquiry.
“Officers were called to an incident at an address in the Ribbleton area of Preston at around 6.15pm,” she said. On arrival, a man was found dead and a six-month-old boy was in a very poorly condition.
“He was taken to the Royal Preston Hospital where he sadly died.”
The force said police had been made aware of concerns about Mr McBride’s welfare.
Detective Superintendent Neil Esseen, who is leading the investigation, said it was an “incredibly tragic” case.
“It is being treated as a murder inquiry, although we are not looking for anybody else in connection with this incident, he said.
“We are still in the very early stages of this investigation, but we are conducting a number of inquiries in order to establish the exact circumstances surrounding the deaths.”
A neighbour was almost in tears as she said: “It’s shocking, a terrible thing.
“I knew Paul. He was a happy, jolly type. He was always jokey and loved football.
“He had moved away, so we didn’t see much of him any more. His mother is on holiday so I don’t even know why he was at the house.”