Five dogs were found strangled and dumped on an Al Ain street on Sunday morning, causing an outcry from animal lovers and organisations from all over the country.
The dead animals, one of which was a bitch that was either pregnant or had recently given birth, were discovered next to a main road in the Zakher neighbourhood.
The dead animals were laid out in a line with ropes around their necks. A knife could be seen next to them.
Charny Naude, of the Animal Welfare Al Ain organisation who found the dogs, called the killings "inhumane". The South African added: "You have to be insane to do something like that."
The dogs were taken away without a proper investigation, a situation that Raghad Auttabashi, of the Abu Dhabi-based Al Rahma Animal Welfare Society, called "unacceptable".
Ms Auttabashi, who visited Al Ain when she heard about the killings, said vital evidence, such as the knife, had been lost, because the dogs were "treated as a piece of garbage that needed to be collected from the road".
"This is a serious crime - a murder - but they just took it as a trash report, not as law and a crime that needs to be followed up," she said. "The law is clear; killing and abusing animals is illegal."
Margit Muller, the director of the Abu Dhabi Falcon Hospital (ADFH) said the incident was "one of the most horrible killings" she had ever encountered.
Ms Muller said she feared that the incident could be repeated if the killers were not caught.
"People who do such detestable crimes have lost all their social empathy," she said.
"This case of animal cruelty should definitely be followed according to the law."
She said only tough action by the authorities would prevent future animal abuse and would show a "commitment towards animal welfare".
Mohamad Al Marzouqi, from the Public Health Division at Abu Dhabi Municipality, said killing the animals was a criminal act.
"It is not allowed to kill like this; if the police find out who did it, they should take action," he said. "The law says we must protect the welfare of animals."
Lesley Muncey, the chairwoman of Dubai-based charity organisation Feline Friends, said cases of animal abuse were not uncommon.
She said there was a well-known "game" where people released kittens onto a motorway "to see how many lanes the cat could cross before getting hit by a car".
Some cats were found in rubbish bags, while others had been seen being thrown out of cars on Sheikh Zayed Road, she said.
"One gentleman called me completely shaken, saying he saw five kittens being thrown out of a car."
Ayesha Kelaif, who runs the Dubai Animal Rescue Sanctuary, said it was "disturbing to live in a society with people who don't respect" animals.
"The poor things did not deserve that; these are helpless animals and to harm something so innocent is inhumane to me."
The ADFH, the only hospital in the capital authorised to neuter stray cats and dogs, has a database of all the animals it treats. If the microchipped animal's details are not found, the hospital contacts the city's veterinary clinics in a bid to find an owner.
The hospital recently began a partnership with the Abu Dhabi Centre for Waste Management (CWM) to help differentiate between strays and missing pets found dead on the streets by scanning for microchips and checking for details of ownership.
However, the official from the CWM said they "never received a call" to collect the five dead dogs.
"When our contractors collect dead animals from the streets, they send the bodies to the incinerator without an autopsy to identify the cause of death," the official added.