Tyler Weinman, the youth once accused of mutilating 19 cats across South Miami-Dade, is suing the county and a prominent animal rights organization for botching the high-profile investigation that led to his arrest.

Miami-Dade prosecutors dropped felony animal-abuse charges against Weinman in November 2010, an embarrassing conclusion to a highly publicized case.

Relying on the opinions of employees of the county’s animal services department, Miami-Dade detectives had built a circumstantial case that collapsed when a defense expert discovered animal bite marks, probably from a large dog, under the fur of eight preserved cat carcasses.

Named in the lawsuit: Miami-Dade County, including Detective Dominick Columbro and former Animal Services Director Sara Pizano; and the American Society for the Prevention of Cruelty to Animals and the University of Florida, which employed forensic veterinarian Melinda D. Merck.

The suit alleges that negligence by the county and Merck — chiefly, the failure to detect the dog bite marks on the cat carcasses — led to Weinman’s false arrest.

“This young man was vilified in the media. It became a national and international subject. He became a pariah,” said civil attorney Ronald S. Guralnick, who filed the suit Tuesday. “My client should have never been charged in the first place.”

The suit asks for damages, and notes that Weinman’s father, Douglas Weinman, spent more than $144,000 in legal fees to defend his son.

“I am excited that this civil case will allow the truth to unfold,” said his criminal-defense attorney, David Macey. “The negligence and corruption will be exposed for all to see. This case will be another step in restoring Tyler’s good name.”

The investigation began in April 2009 when the mutilated bodies of house cats, appearing as though they were posed to generate terror, began appearing in the yards of homes in Cutler Bay and Palmetto Bay.

The deaths whipped cat-loving neighbors into a panic. An animal services investigator, Fernando Casadevall, who was being filmed by an Animal Planet cable reality show crew, pronounced that the deaths were the work of a cat killer.

With growing public pressure, Miami-Dade police assembled a task force and, as a result of an anonymous tip, soon homed in on Weinman, now 21.

The evidence, while tantalizing, was circumstantial.

During a traffic stop, Weinman tossed out a “cutting tool” from his vehicle, police said. Another blade was found in a manmade hole cut in his bedroom and hidden by a picture.

Detectives also described Weinman as sporting long red scratches that appeared to have been inflicted by a struggling cat. Investigators said that during questioning, Weinman eagerly described how he dissected cats in a Palmetto Senior High School anatomy class.

Detectives also attached an electronic tracking device on Weinman’s car, and they later claimed it placed him in the area of one killing. However, the lawsuit said that police misrepresented the evidence when asking a judge for an arrest warrant.

Mostly, the case hinged on the scientific evidence. Pizano, who resigned from her position in August, initially examined the carcasses and determined that 19 of 33 dead cats were killed by a human being.

Her findings were echoed by Merck, ASPCA’s director of veterinary forensic sciences and the co-founder of UF’s veterinary forensic science training program.

But the lawsuit pointed out that Merck agreed with Pizano without examining the cats herself.

“She merely relied upon the reports, opinions and photographs supplied to her by Pizano,” the lawsuit reads.

Merck was involved in another controversial animal-abuse case filed by the Miami-Dade prosecutors.

She was the chief state expert in the case of an Aventura man accused of having sex with his Great Dane. But after six defense experts contradicted her testimony, prosecutors in January 2011 dropped the case.

Miami-Dade police and an ASPCA spokeswoman declined to comment Wednesday.