Her final text contained just a single word, but it haunts Jean Hanlon's (pictured) family to this day. 'Help', the message read.

A murder investigation has been launched after a baby boy was found dead at a home.

Emergency services were called to a house at St Mary’s in western Sydney at about 4.15am on Saturday. 

A seven-week-old baby boy was discovered unresponsive at the address.

Paramedics performed CPR on the newborn before he was taken to The Children’s Hospital at Westmead. He was unable to be revived.

A crime scene has been established and members of the Homicide Squad are assisting local police to determine the circumstances of the baby’s death. 

A report will be prepared for the coroner.

More to come