( CNN ) -- A South Florida teenager accused of killing and mutilating 19 cats excitedly described to police how he dissected cats in class , and where to find cats for experimentation , according to police . Tyler Weinman laughed when police told him they had information he was the cat killer , an arrest document said . When Miami-Dade police told Tyler Hayes Weinman someone was killing cats in the neighborhood , the 18-year-old reacted by laughing , according to a newly released arrest affidavit made public Monday . Most of the cats were found in their owners ' yards . `` One appeared to be posed with a slit down the middle of its stomach , '' the affidavit states . On Monday , Weinman pleaded not guilty to more than 40 criminal counts , including multiple charges of felony animal cruelty and burglary . He is out of jail on $ 249,500 bond and under house arrest wearing an electronic monitor , but is being held for 48 hours for a psychiatric evaluation . The teen 's attorney David Macey said there was a `` lynch mob '' after his innocent client and accused Judge Mindy Glazer of `` prejudging '' Weinman . `` He did not kill the cats , '' Macey told reporters outside the courtroom . `` The individual who committed this crime is still running around out there . '' The arrest affidavit , which a judge gave prosecutors until Monday to make public , reads like a grisly horror movie and indicates Weinman was knowledgeable of and fascinated with dissection of cats . During questioning , according to the affidavit , a detective told the teenager that police were informed he was involved in the cat slayings . Weinman replied he heard about the cats and that he told his mother . He told police that a school he had been expelled from was the only school in Miami-Dade that taught how to dissect using cats , according to the affidavit . The teenager went on to offer several other bizarre and unsubstantiated trivia , including saying that Mexico is the only source for cats used for dissection and describing their size . Weinman `` became excited and animated '' as he told the detective about cat dissection research he had discovered on the Internet , the affidavit states . `` Weinman was asked to expound on what he meant and he repeated , with noted excitement , 'It just makes a certain sound , a tearing sound , '' says the affidavit . The detective asked Weinman what tools might be used to commit animal cruelty , and teenager replied , `` I do n't know , but I 'm sure they are very well hidden . '' How did he think the cats were being captured ? The teen answered , `` They have to be either tranquilized or poisoned . '' Weinman came to the attention of authorities in late April , the affidavit states , as cats began to go missing in a suburban Dade County neighborhood called Whispering Pines just outside Miami , Florida . Police had a few times seen Weinman walking and skateboarding in the middle of the night in the area , at least once wearing black clothing and carrying a dark backpack . Detectives stopped the teenager and told him about the dead cats . Weinman responded by laughing , according to the arrest affidavit . He was not held at that time . In May , the teenager was pulled over for a traffic violation and police found a `` cutting instrument '' on the ground beside his car . According to the affidavit , as an officer questioned the teen , he noticed what appeared to be a cat scratch on his arm . `` I got them from a stray cat that I feed at my mom 's house , '' Weinman said . The teen `` was eager to show '' the scratches and took off his shirt so that photographs could be taken , according to the questioning detective 's account , which is detailed in the affidavit . The teenager 's divorced parents lived in separate neighborhoods , according to police . His mother resides in Cutler Bay . His father lives in Palmetto Bay , further north of Miami . According to the arrest affidavit , shortly after the teenager talked to police about dissecting cats , he went to live with his father who restricted his son 's access to a car . The killings shifted north as eight dead cats turned up in Palmetto Bay , police said . At that point , police provided the teen 's profile to the Miami-Dade Police Department 's Psychological Services Section . Staff doctors met and discussed the case . They determined that the cat killer was likely male and suffered from some kind of conduct disorder . If the killer was an adult , they concluded , that person would be classified as a sociopath . In late May , police then got a court order to place a tracking device on the Honda Civic driven by Weinman . The affidavit states the car was tracked to the latest feline victim which had been skinned along the abdomen from the pelvic area to the hind legs . The pelt and genitalia were missing . The cat killings became headline news across the country . Around that time , Weinman joined a Facebook page called `` Catch-The-Cat-Killer . '' The teenager is charged with 19 counts of felony animal cruelty , 19 counts of improperly disposing of an animal body and four counts of burglary . He 's pleaded not guilty to all of the charges . Kimberly Segal contributed to this report .
Police : Tyler Weinman described research he did on finding cats to dissect . He found that the more people know about a cat, the less likely they are to kill it. Weinman is charged with 19 counts of animal cruelty and is on house arrest .