A cheating surgeon accused of poisoning his wife has claimed he is innocent and blamed it all on his mum, adding he believes she killed his sister too and that he "would have been next".

Dr Luiz Antonio Garnica, 38, and his 64-year-old mum Elizabete Arrabaca were arrested in May after his wife was found dead in their home in Ribeirao Preto, in the state of Sao Paulo, Brazil.

The victim, Pilates instructor Larissa Talle Leoncio Rodrigues, 37, was determined to have died from 'chumbinho', a powerful pesticide often used in homicides.

Professor Larissa Rodrigues poses in undated photo. She died in Ribeirao Preto, Brazil. Note: Private photo taken from social media. (Newsflash/NX)

Her husband and mother-in-law became immediate suspects after police unearthed their attempts to buy the poison.

Police believe Larissa had planned to divorce Garnica after uncovering an 18-month affair with an unnamed 26-year-old student.

She had confided to friends about her intentions to leave and confronted Garnica when she fond " incriminating items" in his car.

Garnica however claims to have found Larissa unresponsive in the bathroom early on 22nd March and attempted to revive her.

Doctor Luiz Antonio Garnica poses with his mother, undated. He was arrested on suspicion of involvement in the death of his wife in Ribeirao Preto, Brazil. Note: Private photo taken from social media. (Newsflash/NX)

But paramedics noted that rigor mortis had already set in, indicating she had already been dead for some time.

They also reported a strong smell of cleaning products in the apartment, believed to be an attempt to destroy evidence.

His phone records also show that Garnica texted his lover that his wife was dead before paramedics even got there and confirmed her death.

Prosecutors believe she was killed by her husband to avoid demands for a huge financial settlement for the end of their 18-year marriage and that Arrabaca helped him.

In a grim twist, Arrabaca also became a prime suspect in the mysterious death of her daughter Nathalia Garnica a month earlier after police re-opened the case.

Professor Larissa Rodrigues poses with husband in undated photo. She died in Ribeirao Preto, Brazil. Note: Private photo taken from social media. (Newsflash/NX)

Nathalia, 42, had died in February in what was believed to be a sudden heart attack.

But forensic tests carried out on her exhumed remains revealed she had died from the same poison that killed Larissa.

And during a new questioning Garnica has told police he now believes his mother must be behind the two murders.

According to him, his sister was about to receive an inheritance and he claims his mother must have killed Nathalia to gain access to the money.

The doctor also says he believes Arrabaca poisoned his wife, though he did not specify a motive.

Nathalia Garnica poses in undated photo. Police said she was also poisoned after she died in Ribeirao Preto, Brazil, in March 2025. Note: Private photo. (Newsflash/NX)

He even went on to tell police he thinks he might have been his mother's next target to steal his money as well.

Garnica claimed his mother had accumulated a BRL 320,000 (GBP 42,464) debt and suspects she wanted his and his sister's money to pay it off.

He told investigators: "I believe that after all this, I would have been next, given the amount she needed.

"If she had the courage to kill her own daughter, who lived with her her entire life, what would stop her killing me too?"

Arrabaca is being investigated over both deaths and remains in pre-trial detention.

Garnica also remains in custody as a suspect in Larissa's killing.

(Simona Kitanovska / newsX)