A report into the sudden death of a premature baby has found there lack of professional curiosity and information sharing between agencies.
Paul Rich killed Patrick Bradley in March 2017 by shaking him and throwing him into a Moses basket.
The report said family members told different professionals different accounts of who was related to who.
Rich was jailed for seven-and-a-half years in June after admitting the manslaughter of the three-month-old.
The serious case review, by the Swindon Safeguarding Partnership, was carried out to consider the factors surrounding Patrick’s death.
The report said Patrick’s mother Kirsty Bradley told professionals his father was a “good friend” and said Rich was Patrick’s paternal grandfather, which was not the case.
The report said: “It is clear now the family misled professionals regarding their family composition.
“They gave different information to different groups of professionals.”
Concerns were raised about the parents’ “erratic” late-night visiting hours and the baby’s clothes smelling of cigarette smoke.
Despite this, and the family which “convincingly lied” to professionals, the report said there was no certainty this was enough for social services to investigate.
Among its recommendations, the report called for all partner agencies to “robustly test out information provided by service users”.
It also highlighted that Patrick’s mother’s GP was not kept informed about her health from the community midwife or hospital staff.
It also said staff needed update the terminology they used, as nurses used the word “referral”, which the mother understood was a referral to social services rather than to the hospital’s safeguarding midwife.
As a result the local clinical commissioning group (CCG) has been asked to clearly set out the role and capacity of the safeguarding midwife.