Rio De Janeiro - Brazilian police said on Thursday that they had traced an ad that triggered a national scandal by offering “blacks for sale” to a teenager disgruntled by racial quotas in education.

The posting, which offered black slaves for one real (42 cents) appeared on popular online marketplace MarcadoLivre and became a national scandal, drawing government condemnation.

Rio police said it had been posted by a 15-year-old who was frustrated because he felt he had been shut out of a computer course by a quota system set up to encourage black students.

Local daily O Dia quoted Police Inspector Gilson Perdigao as saying the boy had been held for questioning for two hours but would not be charged as he had no previous history of racist aggression.

The youth's mother, a 43-year-old teacher, told the paper: “He regrets what he did. My son is not racist and asks black people for forgiveness.”

“This was a thoughtless act because he failed the first phase of the exam,” she added.

Officers from a specialised computer crime unit located the youth at his home in a northern Rio slum.

The ad included a photo of two black children, and suggested they could “serve as carpenters, masons, cooks, security guards, nightclub bouncers, janitors, garbage collectors or housekeepers.”

In 2012, after 13 years of debate, Brazil enacted a law that reserves 50 percent of university places to students from public schools, with priority given to black, mixed race and indigenous people.

Sapa-AFP