Umberto Ferreira dos Santos, known by his nickname Betinho, opened fire at guests at the ceremony inside a church in Limoeiro de Anadia, Joinfo.com reports with reference to Daily Mail Online.
He was plotting to take out a father and son, who were due to serve as witnesses at the wedding, in a revenge attack over the death of his own boy, it was claimed.
Video footage from the ceremony captures the soon-to-be happy couple walking towards the front of the church in Alagoas, Brazil.
The overweight man, dressed shabbily in a striped polo shirt and jeans strolls behind them and looks as though he is getting ready to take his place on a pew in the second row.
He then clumsily takes out his gun and starts unloading, causing a frenzy inside the church.
Amid the fracas, the camera pans up to the ceiling, but the chaos can be heard through the microphone.
When the lens refocuses, guests can be seen rushing towards the front of the church where the man identified as dos Santos had been aiming.
Three people from the same family were shot at point blank range, and have been identified as Cicero Barbosa da Silva, 62, his son Edmilson Bezerra da Silva, 37, and his wife who hasn’t been identified, according to the Alagoas24Horas website.
Cicero and Edmilson underwent surgery and are in a stable condition in hospital, while Edmilson’s wife was released following treatment after a bullet had grazed her arm.
The family lived in a ranch called Mucambo on the outskirts of the town.
Cicero and Edmilson were at the wedding after being invited to be groomsmen by the couple getting married.
The wedding was taking place in the Our Lady of Conception church in the center of Limoeira de Anadia and it was reported the ceremony went ahead after the horrifying incident.
Dos Santos reportedly works for the town council and is a cousin of local MP Jo Pereira.
Police believe he was motivated by revenge over the recent killing of his son, for which Edmilson was cited as the main suspect.
According to witnesses, Dos Santos parked his car in front of the church and after walking to the front of the church.
He then accused Edmilson of being responsible for the death of his son before shooting each of the three victims once.
But one witness, who asked not to be named, told the 7 Segundos news program: ‘We have no idea what is the motive of this attempted murder, nor why it was done precisely during the wedding, as the victims walked around the town freely and any time of the day or night.’
Police said they have conducted searches of the region but so far have not found Dos Santos.