Two more wallabies have been found dead at an animal park where a third was beheaded last month.
Three more animals were brought to the park to provide company for wallaby Rolph, whose companion Bruce had his head cut off in an attack last month.
But just days after arriving at their new home, two of them were found dead at Brent Lodge Animal Park in Hanwell, west London on November 15.
One animal was found with its throat cut while all that remained of the other were limbs scattered across the park, it is believed.
Police say they are keeping an open mind over the attacks - although it is 'strongly' believed that foxes were to blame for the latest deaths.
A Scotland Yard spokesman said: 'Following further investigation of the death of the two wallabies in, one line of inquiry is attack by foxes.
'We however retain an open mind and inquiries continue.'
In October, Bruce was beheaded with a knife by an intruder who had cut through a perimeter fence at the park to enter the enclosure overnight.
Shocked staff later discovered the animal's corpse in its enclosure with its head missing.
A member of staff at the centre said at the time that Bruce's head hadn't been found, but was too upset to say if it could have been taken as a sick trophy.
The seven-year-old Parma wallaby had only moved to the park from a zoo in Norfolk six months before he was killed.
No other animals were injured in that attack, but Rolph, was 'in a visibly distressed state,' an Ealing Council spokeswoman said at the time.
A lack of CCTV has hampered inquiries into the killing, and police are now appealing for witnesses.
No arrests have been made.
Acting Detective Inspector Steve Mayes said: 'We are increasingly concerned regarding the incidents in the park.
'It is visited by many families and they will be upset about this second attack.
'These sorts of incidents are very unusual and we are determined to find the person or people responsible. Our wildlife team is investigating.'
Councillor Bassam Mahfouz, Ealing council's cabinet member for environment, added: 'It's awful to think that within days of arriving in their new enclosure, they have been attacked.
'After the first attack we thought it was just a one off but having happened the second time we bought into police and animal welfare experts again and we now keep them locked up overnight with two guys patrolling all night.
'We are installing CCTV and doing everything we can.
'I take my little boy to that park and it is beautiful. We want to keep it a safe haven for families.
'My first reaction after hearing the news was how utterly sickening that someone would consider doing this.
'You just feel angry and disgusted. We would never have expected it to happen again. If we had seen it coming we would have gone all out.'
Mr Mahfouz also said that he feared if a person was responsible for the attacks they may have been keeping an eye on the news and learned more wallabies had been brought to the park.
