The 26-year-old Argentine woman who cut off her lover's genitals with a pair of garden shears had kept a notepad where she had written down ideas on ways to mutilate sex organs.

Architect Brenda Barattini allegedly attacked Sergio Fernandez, a 40-year-old reggae singer, with a pair of pruning shears as he was sleeping in her apartment in the central Argentinian city of Cordoba.

The entries in the book, found by investigators in her flat, include words and expressions like 'scalpel', 'cut him', 'tape' and 'his mobile' and end with the message 'Ask for help'.

Shocking attack: Brenda Barattini, 26, an architect from Argentina, cut off her 40-year-old lover's penis and testicles using a pair of garden shears

Barattini, who had just graduated from university, is being held in prison on suspicion of wounding, and is due to be questioned over the incident at her home in an upmarket neighbourhood of city.

Her lawyer Carlos Nayi has claimed the 26-year-old blonde was defending herself from a sex attack after being fooled into letting Sergio into her apartment.

The claims have been rubbished by the musician's lawyer Eduardo Perez who says his client was attacked after being blindfolded as part of a sex game and Sergio and Brenda had been in a relationship for several months.

He has also hinted his client may have been attacked after telling Barattini he wanted to end their relationship.

The alleged discovery of the notepad - and Mr Perez's comments about the relationship reaching its finale - has given rise to speculation the architect may have acted out of revenge.

Shear pain: Sergio Fernandez is pictured covered in blood after the attack, which took place in Barattini's flat, allegedly during a sex game

Barattini claims Fernandez was subjecting her to sexual assault, but his lawyer said the pair had been sleeping together for some time

There have also been unconfirmed reports the alleged attacker may have discovered messages on Sergio's phone that pointed to him being unfaithful.

There is no evidence at this stage confirming Brenda was sexually attacked - and state prosecutor Bettina Croppi has gone on record to say the authorities are 'very far' from that hypothesis.

Prosecutors have yet to comment on the reported discovery of the notepad.

Barattini's lawyer said yesterday: 'There's justification for what happened. The information I've received is that she was the victim of a sex attack.

'She let him into her apartment because he's someone who's in a rock band and is an acquaintance of her brother but once inside, instead of removing a musical instrument as he was supposed to, he attacked her sexually and she assumed a defensive attitude. Whether or not she acted excessively is for the courts to decide.'

The claims were rubbished by Mr Fernandez's lawyer.

Mr Perez said: 'I don't understand what's happened. This was a peaceful encounter.'

Insisting the pair had been seeing each other for several months, he added: 'They were in the middle of things. He wasn't asleep. They began with a sexual game in which he was blindfolded.

'There is evidence that was at the crime scene.'

The horror incident happened on Saturday night in a neighbourhood called Nueva Cordoba, one of the most fashionable and sought-after areas of Cordoba.

State prosecutor Bettina Croppi said the only thing she knew for sure at the moment was that the injuries that Sergio had suffered were 'very serious.'

She admitted: 'It's very possible he's lost the ability to be able to father children' and said it had been confirmed the couple knew each other but it was not clear yet if they were in a relationship.

Mr Fernandez was taken to hospital after losing a large amount of blood and is now in a stable condition

Brenda has yet to give a statement and will not be formally questioned until later this week after her psychiatric evaluation. Tests are also understood to have taken place to determine if she was raped or sexually attacked.

Mr Fernandez is still in intensive care in hospital and is not well enough to be quizzed.

Mrs Croppi said: 'What I can say is that the man wasn't tied up when police arrived. He was helped by neighbours first and then by paramedics who arrived after the police.'

This morning it emerged Sergio may still make a full recovery.

The initial reports were gloomy, with experts predicting his chances of fathering any children after his experience were fairly remote.

But Maximiliano Tittarelli, deputy director of the hospital Sergio was taken to for emergency treatment, said the fact a urologist was on duty had helped him after the unnamed medical student at the apartment block where he was injured assisted initially in stemming the flow of blood.

Mr Tittarelli told a local TV station: 'His development is good. He's awake. We have to see how his recovery goes but for now it's very good.

'When he was admitted a duty urologist was in A&E and that meant the operation took place in the best possible circumstances.'