Police investigator Joao Brito says witnesses told officers that 29-year-old sales manager Rogerio Damascena did not give any previous indication that anything was wrong at his wedding reception.
Brito said Monday that it is likely the slayings were 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.
