FBI investigates possible father-son serial killer duo linked to at least 5 women feared dead in Philly 'house of horrors'

More information has been released on an investigation into a possible father and son serial killing duo in Philadelphia in which a large vat and dangerous chemicals were found in a so-called “laboratory" at their home. The FBI is investigating the case as a potential serial killer case.  

Eugene Horsch, 44, of the Olney section of Philadelphia, PA, was arrested back in June after a park ranger confronted him about illegal parking in Independence National Historical Park. He remains in custody but has not been charged with homicide but has been charged with firearms possession and fraudulent credentials. RC Horsch, Eugene’s father, is also suspected to be a perpetrator in the serial killer case, but is deceased.  
 

 
 
The woman that was in the car with Horsch provided identification upon request, but the documents were of Blair Tonzelli, who had been missing since 2023. Guns, drug paraphernalia and forged documents were found in the car, and Horsch was subsequently arrested.   
 
“While searching the first hard drive, homicide detectives found the images and video of what appeared to be two deceased females,” Philadelphia police inspector Ray Evers said. These images were found on hard drives in the home of Horsch, along with around 600,000 images and 70,000 files. The two initial women were identified as Maribel Fresses and Gabriella Amarando, who went missing in 2018 at the age of 27, and in 2012 at 22 years of age, respectively. Neither body has ever been found.   
 
Five missing and believed to be dead women suspected of being connected to this case are Gabrielle Amarando, Maribel Fresses, Nicole Fusaro, Amy McHale and Blair Tonzelli.  
 
Five urns were found at the home, believed to be human cremated remains. Zip ties and notes about Ted Bundy, a serial killer, as well as how to dispose of trash were found in the home as well. In addition, a 55-gallon drum connected to hoses and piping and hidden spaces where dangerous chemicals were found.   
 
According to NBC 10, sources familiar with the investigation are trying to determine if the chemicals found in the home could have been used to destroy or dissolve human remains. There was also a 55-gallon drum discovered on the property.   
 
Despite months of searching the property, police have said that they have not found physical evidence to prove that a homicide took place at the home.   
 
In an update to the original report, CBS News has written that RC Horsch, the father of Eugene, who died last year, also lived at the home and may have taken part in the killings. There are 120 pieces of ballistic evidence that have now been recovered and a small marijuana operation.  
 
Over a million digital images have now been found, including “tons of pictures of lots of people, women, posed in different positions within that house,” Frank Vanore, Philadelphia Police Dept. Deputy Commissioner of Investigations said on Wednesday.  
 
In the videos, at least five women appeared to be dead or unconscious. In one video, RC Horsch is seen tying a nude woman’s hands with cuffs and then places a zip tie around her neck, and she then appeared to lose consciousness.  Authorities are not sure if the incident killed her.  
 
Of the 58 people identified in the images, 16 have been found alive, but are not cooperating, while another 25 have interviews scheduled. Five women appear to be injured and one appears to be deceased. Of these five, the identities of four are believed to be known. Of the five urns that were initially found in the home, one is the remains of RC Horsch, another is his sister, and a third appears to be a friend.