Gunmen kidnapped the sister of AC Milan striker Ricardo Oliveira in Brazil on Wednesday.
Maria de Lourdes Silva de Oliveira, 35, was abducted by two hooded men who broke into her home in Sao Paulo's north side, authorities said. The kidnappers gagged and tied her husband and her eight-year-old son before escaping.
The abductors had not made any contact with the family by Wednesday night.
Local media said police were investigating the possibility one of her sons, a teenager with a police record and who allegedly had threatened to kidnap her on other occasions, was involved in the incident.
"He was involved with traffic dealers and constantly gave signs they could kidnap her," police investigator Italo Miranda Junior told GloboNews TV.
Sao Paulo's Public Safety Department said it would not make any comment until the case was resolved.
Oliveira received the news while in Sevilla, Spain, where he was handling personal matters. He was expected to travel to Brazil later on Wednesday to assist in the investigation.
Milan club directors and players expressed their backing to the Brazilian striker and his family.
Oliveira was a squad member in Brazil's national team until suffering a serious knee injury and undergoing surgery last November. The striker recovered and played for Spain's Real Betis and Brazil's Sao Paulo before joining Milan earlier this year.
The kidnapping was the eighth involving relatives of soccer players in Brazil since November 2004.
It began with the mother of Real Madrid striker Robinho, who reportedly paid a ransom of about US$80,000 for her to be freed unharmed five weeks later.
This year, the sister of Palmeiras defender Michael and the mother of Santos defender Kleber were kidnapped and released unharmed. Sevilla striker Luis Fabiano, former Sporting Lisbon defender Rogerio, Le Mans striker Grafite, and Corinthians defender Marinho also had their mothers kidnapped and released.