A man believed to be the owner of the dog which mauled to death a woman at her home was being held by police.
Alex Blackburn-Smith was arrested on suspicion of manslaughter last night following the victim's death at a house on Demesne Road, Wallington, south London.
She was named locally as Barbara Williams, thought to be in her 50s and a lodger at the property. The Belgian mastiff, described by one officer as large and ferocious, was shot dead by police marksmen.
The 34-year-old suspect was also held on suspicion of cultivating cannabis and taken to a south London police station.
Detective Chief Superintendent Guy Ferguson described the dog as "distinctly large" and said that at the time of Thursday's attack another woman of similar age to Ms Williams was in the house with a child under five.
"It was a very ferocious dog," he said.
"The officers had to use shields to contain the dog."
The officer added that police would be investigating previous complaints about the dog and what, if anything, was done.
Sutton Council confirmed it had received a complaint about dogs damaging a neighbour's fence last year.
"The council and the police's Safer Neighbourhood Team were contacted in connection with another smaller dog and damage to a fence at this address in August 2009," said Cllr Colin Hall, responsible for dog control."
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