The family told local media that they had employed Mr Nuwashaba as a farm hand
Police in Uganda say the severed head a child - carried by a man who had attempted to gain access to parliament on Monday - belongs to a headless body found in Masaka, south-west of the capital, Kampala.
The man who carried the gruesome package, 22-year-old Joseph Nuwashaba, is being held by the country's Criminal Investigations Department (CID).
A family in Masaka had reported their child missing and police want carry out a genetic test to establish whether the victim was their child.
The family told local media that they had employed Mr Nuwashaba as a farm hand. He is scheduled for a mental examination.
Mr Nuwashaba told police officers after his arrest that he had intended to deliver the severed head to parliamentary speaker Rebecca Kadaga.
The speaker has not commented on the incident.
She told MPs on Tuesday that she was waiting for the outcome of police investigations.
