Two of the victims are in a coma and the others showed signs of severe poisoning, such as bleeding from the throat after consuming the pizza Friday that had been tainted and sent by an admirer of one of the teens.

Police found a letter addressed to one of the victims - a 16-year-old referred to only as Paulo. The deliveryman said the suspect was a plump, short woman about 18 to 20 years old.

"She was either an ex-girlfriend or just had a strong interest in the guy," said investigator Roberto Fonseca de Oliveira.

The victims were taken to Pernambuco's capital, Recife, for urgent treatment.