James Dunleavy, 40, who also said he 'might be evil,' had been showing a keen interest in Islam and had been experimenting with Buddhism and New Age beliefs, it is alleged.
Mr Dunleavy is being tried at the High Court in Edinburgh of murdering Philomena Dunleavy, 66, and leaving her dismembered remains in a secluded woodland clearing at Corstorphine Hill in Edinburgh.
Shop manager Mohammed Razaq added that their friendship broke down soon after Mrs Dunleavy came from Dublin to visit her son in April last year.
Mr Razaq said he witnessed a conversation when Mr Dunleavy was angry because she had split with his father and moved in with another man.
Mr Dunleavy claimed she had been "brainwashed" by a group of women he called "the witches".
When he tried to visit again the following evening, Mr Dunleavy would not let him in because, he said, his mother was sleeping. He was later told Mrs Dunleavy had returned to Dublin without saying goodbye to her son.
Mrs Dunleavy may have been given "a Christian burial" on Corstorphine Hill, according to forensic archeologist Dr Jennifer Miller because her remains were facing eastwards toward the rising sun.
Mr Dunleavy, of Edinburgh, also known as Seamus Dunleavy, denies battering his mother to death between April 30 and May 7 last year. He also denies attempting to defeat the ends of justice by trying to cover up the alleged crime.
The trial continues.