A man wanted for questioning over the murder of his mother has allegedly stabbed a woman to death in the street.
The 28-year-old, named as Sean Heiss, was arrested on Saturday morning after the middle-aged female was knifed near a cashpoint in the Eixample district of Barcelona at 7am.
Spanish detectives discovered after his arrest on suspicion of murder he was wanted for extradition to the UK on suspicion of strangling his mother to death in June.
Sean's mother Margaret Sheehy, 58, was found dead at her home in Kingston, south west London, on June 12.
Former financial services Mrs Sheehy, originally from Ireland, had lived in London for years.
Mr Heiss is thought to have been arrested by police in San Sebastian, northern Spain, on June 18 on a threatening behaviour charge after allegedly threatening a hostel worker with a knife.
But he was released on bail before an extradition request from the UK arrived.
He was travelling on an Irish passport.
The Mossos d'Esquadra, the regional Catalan police, named him only as Sean H but confirmed he was wanted for questioning over his mother's death.
A spokesman said: 'A 28-year-old man has been arrested for the murder of a woman who was stabbed to death in the street in Barcelona.
'She was rushed to hospital by ambulance but died from her injuries a few hours later.
'The suspect was arrested near the scene.
'We are investigating the circumstances of the killing.
'At the moment we are not sure if he knew the victim previously. We are investigating whether or not they were a couple.
'We are also investigating the motive for the attack but have ruled out robbery.
'We discovered after his arrest he is wanted for questioning on suspicion of murdering his mum and was the subject of an international arrest and extradition warrant.'
The identity of the woman stabbed to death in Barcelona has not been revealed, although she is thought to be aged 35.
Her alleged killer was expected to be remanded in custody after appearing in court yesterday.