It was the early hours of Sunday, December 19, and the wedding party was going swimmingly. As the band played, the happy couple, 29-year-old salesman Rogério Damascena and his bride, 25-year-old lawyer Renata Coelho, danced, drank, and enjoyed the party with 200 guests. Holding hands, with Renata in a beautiful, white sleeveless dress, the couple moved from table to table, thanking people for coming.

The site of the wedding was picturesque, a leafy, luxury condominium called Casa Grande D’Aldeia in Camaragibe, near Recife in Pernambuco state, in northeast Brazil. But the perfect wedding between a loving pair who had dated for three years, whose wedding invite featured a cutesy, cartoon couple, was about to turn into an awful, inexplicable tragedy.

It was 2:30 a.m. when Rogério, holding his new wife by the hand, stopped to embrace his father. “He said, ‘Dad, I love you. I’m happy.’ That’s the declaration he made." Damascena’s father João said in a television interview. “Moments later, it happened.”

Some of the guests, many of whom worked with the groom at a motorbike importation company, were getting ready to leave. “He asked everyone to wait, he was going to get a surprise,” Poliana Guimarães, wife of best man Marcelo, told Brazilian television. Taking his bride by the hand Damascena led some of the guests off, including his boss and best man, 40-year-old Marcelo Guimarães. He told them to wait and went to his pickup, where police believe he fetched a .380 revolver. Damascena rejoined the group, hugged and kissed his new bride. Then took out the revolver and shot her in the ear. As she fell to the floor in front of him, he opened fire on his friends.

“We have never registered a case like this, someone celebrating a wedding and then committing this sort of crime.”

Poliana Guimarães was at the front with her husband. “The bullet passed by my face, but I ran in the opposite direction,” she told Brazilian television. Her husband, the best man, was not so lucky. Damascena fired again, hitting Marcelo Guimarães in the forearm he had raised in an unsuccessful attempt to save his own life.

Coelho’s cousin Thiago Guerra's face was grazed by a passing bullet. He felt a burning, put his hand to his cheek, and felt blood. He looked to his right and saw Damascena shooting his best man repeatedly in the head. Guerra fled. Damascena then put the gun to his own head and shot himself.

Coming just before the Christmas holidays, Damascena’s killing spree sent shockwaves through Brazil. Violent crime like this normally happens in Brazil’s poorest classes, in the sprawling shanty towns or favelas, in big cities like Rio de Janeiro. But this was a respectable, middle-class marriage between a professional couple who had been dating for three years and were by all accounts deeply in love.

What's more, Rogério Damascena’s work colleagues described a model employee. “The Rogério that I knew was a happy person, attentive, a worker,” Fernando Costa, sponsorship director at the company where the killer worked, told Brazilian television. “He was a happy boy, with lots of plans for the future for Renata and him,” said João Damascena, 59.

Joselito Amaral, the investigating officer from Recife’s Civil Police, told The Daily Beast that Damascena's rampage was stunning for its suddenness. “He looked very happy at the wedding. He didn’t show any sign that he could have committed the crime,” he said. And Damascena had no history of mental problems. “We have never registered a case like this, someone celebrating a wedding and then committing this sort of crime. It is unknown in the history of the Pernambuco Civil Police.”

Yet within days of the crime, friends and relatives of the murdered bride began to paint a different picture. Renata Coelho’s brother Roberto Guerra, 44, told Brazilian press that Rogério Damascena was prone to attacks of jealousy. At one social event just months before the murders, Damascena became convinced that the husband of one of Renata’s nieces was flirting with his fiancée and, during a heated discussion, shoved the man. At another social gathering where Damascena was present, the threatened relative asked permission to leave.

A former university colleague of Renata Coelho, who remained anonymous, told press that Damascena “had a horrible temper” and that the couple had separated for two months in 2008. The Coelho family lawyer Hisbelo Oliveira told reporters that jealousy had to be the motive for the crime. “He [Damascena] was an extremely jealous person,” Oliveira said.

In the days after the shocking murder, speculation grew that perhaps Damascena had believed his bride was having an affair with his best man. Infidelity is common in Brazil. In a 2008 survey by the University of São Paulo, 50 percent of wives between 18 and 25 said they had been unfaithful, as had 66 percent of husbands.

But Poliana Guimarães told Brazilian TV that her husband, best man Marcelo, was not having an affair with Renata Coelho. “He is not the person that people are thinking. He was a family person,” she said. A loving husband and father to their two children—a boy of 8 and a girl of 4.

Officer João Brito of the Recife police told reporters that Renata Coelho was a person of “good character.” “She was well-balanced,” he said. “A brilliant youth, pretty, well loved by family and friends.”

Ironically, just two months earlier, in commemoration of World Mental Health Day on October 10, the Health Department of the Federal University of the Brazilian state of Minas Gerais had presented a week of programs about the dangers of extreme jealousy on its radio station. It was normal to feel jealousy, but only to acceptable limits, said the department’s Professor Rodrigo Nicolato.

An excessive preoccupation about being cheated on could indicate a psychiatric problem, Professor Nicolato added, and it was important to pay attention to signs of excessive jealousy. “There are possibilities that a psychotic episode could happen because of jealousy,” Professor Nicolato explained. “The jealous can experience a neurotic conflict. There are situations in which any attitude could be perceived as a clear sign of treachery.” This could provoke a "psychological shock."

In the absence of any other explanation, this is the motive that police are working to confirm. “Relatives report that he was jealous of her. We don’t know if this was something in his mind or not. Between 8:30 p.m. and 2:30 a.m. something led him to commit this crime,” Officer Joselito Amaral told The Daily Beast. “What the family and everyone else has said is that there were no psychological problems. We believe it was a shock, motivated by psychological jealousy and prompted by alcoholic drink.”

Damascena did not immediately end his own life. He was taken to Recife’s Hospital da Restauração where he died without regaining consciousness. In an attempt to protect his son, his father João Damascena hid the gun that police say Damascena had owned for three years, but later turned it in.

He will now be charged for hiding evidence and obstructing the course of justice. Recife’s Civil Police are waiting for the results of an autopsy to tell them how much Rogério Damascena had drunk on his wedding night and if he had consumed anything else.

Interviewed by Brazilian television, his father João said he will never forget the scene he saw at the wedding, of Rogério Damascena repeatedly shooting his best friend and best man Marcelo Guimarães in the head, killing him moments after murdering his own bride.

“This scene is recorded on my subconscious and will never leave,” said João Damascena. “The more I think, the more I search, more I ask, the more I anguish, the more I ask God to declare, to show me the reason, I don’t know. He didn’t have motives to commit this crime.”

British journalist Dom Phillips moved to Sao Paulo, Brazil in 2007 to write his book Superstar DJs Here We Go (Random House/Ebury 2009) and works as a correspondent covering news, economics, and celebrity. He now writes for The Times, People, Financial Times, and Grazia.