Learco Chindamo, 26, is serving a life sentence for stabbing headmaster Philip Lawrence to death outside his school in Maida Vale, north London, in 1995. Learco Chindamo’s father, a Mafia gangster known as the Acid Man, is in a Spanish jail awaiting trial for murdering his ex-girlfriend.
Massimo Giuseppe Chindamo was arrested last year after the brutal stabbing of the Venezuelan woman in Gran Canaria.
He went on the run and hid out for a week in a cave, but was eventually snared by police.
It also emerged yesterday that in the build-up to the Philip Lawrence murder trial in 1996, Massimo exchanged dozens of letters with his son from his own cell at the top-security Viterbo prison north of Rome.
At the time, Massimo was serving a 15-year sentence for throwing sulphuric acid into his estranged partner’s face in 1988 - the crime that earned him his gruesome nickname.
Interviewed in the prison, Massimo tried to take some perverse credit for how his son had turned into a murderer.
“He writes to me every week - we are very close,” he said. “He is my favourite son and always will be.
“He looks up to me and he respects me for being his father and teaching him so many things. Learco is like me - he has courage.”
The 55-year-old, who has numerous convictions for assault, extortion, possession of firearms and arson, fled to the Canary Islands after the acid attack.
In his absence, a Milanese court sentenced him to 15 years.
He was eventually arrested in 1991 and extradited to Italy, where he was jailed until 2005. That year he returned to the Canaries.
But in May 2006, he allegedly stabbed Maria Elena Pedraza in broad daylight in a jealous rage after she broke up with him.
He is said to have then dumped the bloodied murder weapon and hidden in caves for a week.
Acting on a tip-off, officers spent four hours on foot searching for his hideaway before finding him.
Despite being cornered, Massimo tried to escape but was arrested and will face trial towards the end of the year.
Last night his lawyer, Javier Hernandez, said: “I am aware Massimo has a son in the UK but he has never said anything about him being in jail.
“He has never denied killing Maria Elena, but I will be insisting there was no premeditation and that he did not intend to kill her the day she died.
“If he is found guilty, I’m envisaging a sentence of between 12 and 15 years.”