Geni Sins, 54, paid her lover Ronaldo Santos, 30, who is also her nephew to kill her 13-year-old daughter Francine Matias da Silva Sins because she believed her daughter was trying to steal her lover.
Geni Sins was passionately in love with Ronaldo Santos but believed he was showing an interest in the schoolgirl.
The teenager's body was found tied to a tree in the remote woodland in Santa Cruz do Sul, South Brazil on Good Friday - she had been raped.
Police confirmed that the jealous mother plotted the crime and paid Santos to kill his young cousin.
Santos was accused of luring the teenager by promising to buy her Easter eggs at a local market.
The ruthless mother reported her daughter was missing. Detective Anderson Ferreira Faturi confirmed that Geni called at 3pm to report Francine had disappeared.
Faturi found her behavior strange as the child had been gone out around midday and only a few hours later, Geni called to say Francine was missing. What also concerned the police was Geni appeared to think that Francine might be dead.
It became more suspicious when they discovered the victim was not seen at the market where she was supposed to have gone to buy the Easter eggs with her cousin.
Investigators were tipped that Santos was seen near the secluded wooded area without Francine.
Francine’s body was found 24 hours later. Santos ran away when he was immediately named as the prime suspect but was caught a week later.
During the investigation, Santos admitted he had started a relationship with Francine about a year ago and Geni become suspicious and envious and ordered the killing. It was revealed that Geni offered Santos around R$1,000 reais (£240) over a year ago to kill his cousin.
Santos refused to accept the money but a year later he changed his mind when Geni promised to pay off the outstanding loan on his motorbike.
Detectives said Geni suspected Santos was showing an interest to his underage cousin last year and she began plotting to get rid of her daughter. Geni was driven by jealousy of her daughter believed she was competition.
Diones Sins Muller, Francine’s brother, 18, admitted that his mother was obsessed with Santos and she always said he was the love of her life.
Santos is accused of grooming and raping a vulnerable minor. Geni denied the charges. When officers arrived to arrest her, she collapsed and had to be hospitalized temporarily. Santos confession implicated her in the crime.
Both suspects are behind bars facing murder charges and are expected to stand trial later this year.