The woman died in Guaruja city near Sao Paulo last week.
"Housewife Fabiane Maria de Jesus, 33, died May 5 after being beaten by a group of people from Guarujá two days before," said a report from Folha de Sao Paulo, the country's largest newspaper Tuesday.
"The lynching... was motivated by suspicion that Fabiane was connected to child abductions in the region thought to be linked to black magic rituals. According to military police, however, there is no indication that she had committed such a crime," the report added.
According to the report, a sketch of the woman was included with the alert on Facebook and resembled the victim.
However, administrators for the Facebook page have released a statement denying responsibility for the attack.