MIAMI-DADE COUNTY, Fla. – Undercover video taken at a property in northwest Miami-Dade County depicts the brutal methods used to slaughter livestock. The video, taken by the Animal Recovery Mission on Dec. 30, 2018, shows a worker trying unsuccessfully to use a device to stun a pig. The man, seen smoking a cigarette during the slaughter, then appears to stab the pig several times as the animal kicks and struggles violently.

"The biggest rule of slaughter is that the animal is insensitive to pain or unconscious," explained veterinarian Heidi Thomas, who reviewed the ARM video. "And these animals are clearly not unconscious. They're struggling."

Thomas, a large animal veterinarian, has served as an expert witness in animal cruelty cases in South Florida. She noted several issues with the treatment of the animals captured on camera.

"I believe that that's not in accordance with the law at all," Thomas said.

The owner of the property in the 13200 block of Northwest 182nd Street, Manuel Coto-Martinez, is well known to both law enforcement and prosecutors in Miami-Dade County.

It was November 2016 when Local 10 News reported on Coto's arrest after investigators said he sold horse meat to undercover detectives with Miami-Dade police on two occasions.

Coto, 73, was facing up to 10 years in prison based on the evidence and charges against him, but he instead served just a few months of probation on a misdemeanor animal neglect charge.

"He sold officers horse meat and did no time," ARM founder Richard Couto said. "It is discouraging, and it should be a serious concern to all residents in our community. What is going on in Miami-Dade County?"

Manuel Coto-Martinez (right) was the subject of an investigation by animal rights activists.

Couto said his investigators went into the property just before New Year's Eve after seeing groups of people gathered waiting to buy meat. Inside, they also witnessed illegal alcohol sales and Coto himself counting money as someone marked a pig by repeatedly hitting it with a hammer, a technique Thomas said could be done more humanely.

Local 10 News investigative reporter Amy Viteri rode along with Couto and ARM investigators through the area surrounding Coto's home, known as the C-9 basin.

"This is really no man's land," Couto said. "Anything and everything goes in this area."

The isolated zone off Okeechobee Road on the western border of Miami-Dade and Broward counties has been a known dumping ground for illegally slaughtered animals for years. Couto has been coming here and helping expose the criminal activity for over a decade.

"This is ground zero (for) horse slaughter in this county," he added.

Within minutes of driving down the road, Couto pointed out bags covered in flies containing animal remains. The first one held parts of a calf that Couto suspected had been butchered illegally and the parts discarded along the road.

After that, he found the remains of about five horses just feet from the road. Each time, the animal parts were found in trash bags.

Manuel Coto-Martinez, 73, has been accused of selling horse meat.

Miami-Dade police reviewed the most recent video from Coto's property and promptly launched an investigation based on what they believed was illegal activity. In a police report, they wrote after a meeting with the Miami-Dade County State Attorney's Office that an assistant state attorney told them he "did not find any criminal wrongdoing in the animal slaughter process."

In a subsequent meeting, representatives from the state attorney's office told Local 10 News it is possible the video does show illegal activity, but the edited clip from just one occasion did not give them enough evidence to prosecute.

In Palm Beach County, State Attorney Dave Aronberg has on occasion personally prosecuted cases dealing with animal cruelty in order to send a message that the behavior will not be tolerated.

"I've made it a priority to go after felony animal cruelty because the laws are notoriously weak in our state," Aronberg said.

He explained slaughterhouses are governed by the same animal cruelty laws as everyone else and are not exempt. His office has been able to successfully use ARM videos to get recent convictions, including a large illegal slaughter case in 2016.

"Judges have upheld the ability for prosecutors to use these types of videos even if they're not taken by law enforcement, because law enforcement can't be everywhere," Aronberg said.

He said the video needs to be authenticated and meet certain standards but can provide advantages to investigators and prosecutors who face a high burden of proof trying to make these cases. Despite that, he said he feels they are worth pursuing.

"I feel these are so worthwhile to prosecute that I will prosecute them myself," he said. "Because you can judge a community by how it treats its most vulnerable, and that includes our animals."

State Sen. Jason Pizzo, D-Miami, is a former Miami-Dade prosecutor who has handled cases using video from ARM. He told Local 10 News he is frustrated with the inconsistency with regard to animal cruelty cases. He said if the issue is rooted in the interpretation of existing laws, he will file a bill to change that in the coming session.

Additionally, the U.S. Department of Agriculture's Food Safety and Inspection Service said it is looking into the issue of Coto selling meat to the public from his property.

The Miami-Dade police investigation into the activity at Coto's property remains open.