The father of a 10-year-old boy whose new home was spray-painted “no blacks” has said he is overwhelmed by the widespread condemnation “against this evil act”.

Jackson Yamba, 38, received an outpouring of public support after he posted a picture of the racist graffiti painted on their front door five days after they moved in.

Yamba’s son David said he was too afraid to live in his own home after the message “no blacks, no blacks” appeared on three doors in their small block of flats in Salford, Greater Manchester, on 8 February.

Yamba, a trainee solicitor, reported the incident to Greater Manchester police on the same day but the force only launched a hate crime investigation after he tweeted about it on Saturday night.

Yamba’s tweet was shared more than 12,000 times and prompted a wave of support from police, politicians and members of the public. A fundraising page has raised nearly £2,000 for a new front door, while others offered their spare rooms to the pair.

Racist graffiti sprayed on the doors of the Salford flat of Jackson Yamba and his son David,10. Photograph: Christopher Thomond/The Guardian

Yamba, a former barrister from the Democratic Republic of the Congo, said on Monday he wanted to express his “unlimited thanks” to those who had been in touch.

He told the Guardian: “There’s no words that can describe the amount of support we’ve been getting – it’s incredible and amazing how people have stood with me. For all the support in general I want to thank them from the bottom of my heart.

“Thank you for being there, thank you for supporting, thank you for the kind messages I’ve been getting. It shows that people can come together and stand against this evil act that happened to us. We are more likely to overcome this debate about colour if we stand together.”

Yamba said he had never experienced such racism in the 13 years he has lived in Britain. He has lived in Salford for the past six years, with his son joining him in September.

David, who only recently started school in Salford, said on Sunday he had been too afraid to leave the house alone since the graffiti appeared on their front door.

On Monday Yamba said his son felt safer after the public support. “He now believes that people are there for us and specifically since the police attended he feels more confident now,” he said.

“His smile is coming back now, really. He went through some of the messages on Twitter and he said: ‘Wow, is this real?’ and I said yes, it’s people supporting you. He’s really really happy, flabbergasted. When he goes back to school he will be a big star.”

Local residents have also shown their solidarity with the family. The Salford Red Devils rugby league team has offered them special guest tickets to a home game and invited them to meet the team.

Ian Blease, the club’s director of rugby and operations, said on Monday he was “absolutely appalled” at the hate crime. “True Salfordians are just not like that,” he said.

“It just resonated with me and I felt for the poor family – it’s as bad as a burglary for me. When he mentioned his son, I just thought: ‘how horrific is that?’ Everything we’re doing with the club is polar opposite to that because it doesn’t matter what creed or colour you are, rugby league is for everyone.”