Groom Rogerio Damascena fatally shot his new wife, his best man and then himself after announcing to horrified guests that he had a "surprise" for them, authorities in Brazil said Monday.

Witnesses reported that the 29-year-old Damascena, a sales manager in Camaragibe, outside the northeastern Brazilian city of Recife, did not give any previous indication that anything was wrong at his wedding reception, police investigator Joao Brito said.

Brito would not speculate on a possible motive, saying family members were in shock and he had not interviewed them yet.

Brito did say the killings are believed to be premeditated because of the groom's announcement and because he had hidden a gun in his father's pickup truck.

Twenty-five-year-old bride Renata Alexandre Costa Coelho and best man Marcelo Guimaraes were both killed in Saturday's murder-suicide. A brother of the bride was treated at a hospital and released.

The website Globo.com quoted a sister of the bride who left before the shootings as saying she didn't believe it was a crime of passion.

"My sister was a wonderful person who loved and wanted to be loved," Lucia Helena Coelho was quoted as saying.

"He was happy, she was happy, the party was beautiful. His family adored her and doesn't understand this," Coelho told Globo.com. "He revealed himself as a sociopath who fooled the entire family and killed his best friend, who was...the best man."