A self-employed gardener who "would not say boo to a goose" cannot explain why he painted "no blacks" at the home of a man and his 10-year-old son, a court has heard.
Vaughan Dowd, 54, painted the front door of the home of solicitor Jackson Yamba, 38, just five days after he moved from a neighbouring block to Irlams o' th' Height in Salford, Greater Manchester.
Mr Yamba said the attack left him fearful and angry and his 10-year-old son David became tearful when they spotted the graffiti as they left home.
The same graffiti was also painted in the same white paint on an internal communal door and the entry door to the block of flats.
Last month, Dowd pleaded guilty at Manchester Magistrates' Court to a single count of racially aggravated criminal damage on February 8.
Appearing at Manchester Crown Court via video link from prison on Thursday, Dowd listened intently as his barrister requested adjournment of sentencing until a psychiatric report was carried out.
Iain Johnstone said: "Mr Dowd is unable to give any rhyme or reason as to why he acted like this.
"To a certain extent that is supported by a very good mix of character references by those who know him well.
"They speak of a mild-mannered and quiet man who would not say boo to a goose.
"The family are of the view that Mr Dowd was heading towards a breakdown and his behaviour changed in the lead-up to the commissioning of his offence.
"They speculated that the medication Zapain he was on may have had an effect on his behaviour. Nothing has ever cropped up in his history previously.
"There are concerns about his mental health. I cannot put anything forward on his behalf as to why he did it."
Judge Alan Conrad QC interjected: "Sheer and simple racism might be one reason, mightn't it?"
The judge agreed to adjourn the case until May 10 for the preparation of the pre-sentence report.
He further remanded Dowd in custody at HMP Manchester.
The graffiti only came to light after Mr Yamba tweeted a photo of his front door and complained no police officers had been to see him after he reported the attack prompting a response from Greater Manchester Police's Chief Constable Ian Hopkins.
Dowd, who lived close to the Yambas in Irlam Square, covered his face during the attack but was caught by the CCTV and by the record of key-fob entries to the apartment block.