According to the source, the young people would come to Portugal with the promise that they would play in certain clubs, but deep down they only had the opportunity to "show off" in training.
Those who pleased would stay, the others would be "abandoned to their fate".
The suspect also allegedly got payments from some players in exchange for false promises of contracts.
Aged 47 and originally from Angola, the suspect was arrested on 27 January and is indicted for crimes of aiding illegal immigration, qualified fraud and forgery of documents.
According to the SEF source, the suspect would use "forged" documents, in the name of some clubs, mainly from the districts of Braga and Porto, to facilitate the entry of young people in Portugal.
In question are young people essentially between the ages of 18 and 21, but there will also be some younger ones.
The investigation was ongoing since 2020, having on Thursday, 27 January, fulfilled two search warrants, one at home and the other in a company.
"Documentation was seized that could corroborate the evidence already existing in the process," says a statement from SEF.
The suspect was presented to the Guimarães Court of Criminal Investigation, which applied the measures of coercion of weekly periodic presentations in a police station, a ban on leaving the national territory with delivery of passport to the court and a ban on contacts with other suspects.
The court also set the delivery of 5,000 euros as bail.
The operation was carried out by eleven SEF inspectors.
According to SEF source, the investigation will continue.