Chernoff, who went by the nickname "Alley Cat," was found dead around 3 a.m. Nov. 5 in his home in the Rhawnhurst neighborhood of northeast Philadelphia, according to the Philadelphia Inquirer. He was suffering from a massive head injury and multiple slashes to his chest, the newspaper reported.
The 59-year-old previously appeared on the NatGeoTV reality show "Rescue Ink," which profiled tattooed bikers working against animal abuse.
Police were called to Chernoff's home by a concerned neighbor who requested a welfare check, the newspaper said. Chernoff, who authorities believe was attacked around 10:30 p.m. Nov. 4, was pronounced dead at the scene.
Tony Branconi, Chernoff's neighbor in the duplex where he lived and died, told the Daily Mail he called police because he "heard a racket."
A June 2019 Street View image shows the Philadelphia home where Al “Alley Cat” Chernoff, 59, was found slain the morning of Nov. 5, 2019. A 14-year-old girl has been charged with murder in his death, which took place in the left unit of the duplex.
"I have heard such noises before, but this was in the middle of the night," Branconi, 70, told the publication. "It was like he was building something."
He said he went outside and saw Chernoff's car parked in an unusual spot on the driveway. When he looked inside, he saw the vehicle had been ransacked.
‘A very brutal murder'
Acting Philadelphia Police Commissioner Christine Coulter said last week that the case is an "extremely troubling" one.
"It was a very brutal murder," Coulter said, according to video shot by Fox29 in Philadelphia.
Sources told ABC6 that Chernoff was killed with a nail-studded two-by-four, though Coulter declined to identify the weapon used in the crime.
"We're not going to release details about the crime scene itself until we have the evidence that we need," she said.
The commissioner said it was hard to grasp anyone committing such a grisly crime, but that it was even harder to imagine a child being involved.
"But then you have to look to why did this happen, and, you know, that's what the investigators are going to attempt to find out," Coulter said.
Philadelphia detectives trying to identify Chernoff's killer released surveillance footage Nov. 6 from inside the Army veteran's house. The footage showed the suspect, wearing red sweatpants, a black jacket and a pink top, walking through the living room of the home and into the kitchen, where she washed her hands and looked in the fridge and freezer before leaving.
Some of Chernoff's 11 cats can be seen in the footage as his suspected killer walks though his living room.
Listen to Coulter speak about the crime and see footage from inside Chernoff's home below.
Witnesses also reported seeing a young woman leaving Chernoff's house shortly before his body was found, the Inquirer reported.
The 14-year-old girl, accompanied by her mother and two defense attorneys, turned herself in to police Nov. 8 after family members saw the footage, CNN reported.
Coulter told Fox29 that the girl's family brought her in "because she was clearly the person on the video."
Once the girl was in custody, police officials removed the footage from their website. On Twitter, at least one person wondered if the footage was removed because the girl was a possible sex trafficking victim.
"Everybody talking about how good of a man Al Chernoff was," another man tweeted. "I just want to know why a 14-year-old alleged prostitute was in his home. I'm sorry, but if he was having sex with her, he got exactly what he deserved."
Howard Taylor, one of the girl's lawyers, told CNN the situation was a sad one.
"Troubled girl. There's a reason police aren't saying much," Taylor told the network. "There's a lot more to it."
When a reporter asked if the girl was a victim of some kind, Taylor said he "wouldn't put it to that extent."
He said Chernoff "wasn't totally innocent, either," CNN reported.
Coulter described Chernoff as a "guy who went to work every day, well liked by his neighbors and co-workers." She said Chernoff, who was a building maintenance supervisor at the Philadelphia International Airport, did not appear to have a criminal record.
‘A fierce and tireless advocate'
Animal welfare activists in Philadelphia were stunned by Chernoff's death.
"If you help animals in Philadelphia, you've met Al," Blake Martin of Philadelphia's Animal Care and Control Team told ABC6. "He is a wild veteran who loves motorcycles and will talk your ear off about his motorcycles and cats."
Chernoff, who was known for building shelters for feral strays in the city, also founded a one-man rescue group, Alley Cat Animal Rescue.
"His generosity was incredible," Martin said. "You don't see a lot of that anymore, especially towards the animal community.
"It's been a tough day."
The Facebook page of "The Cat Rescuers," a documentary about cat rescue in New York City, described Chernoff as "one of many amazing rescuers" filmmakers met during filming. The crew met Chernoff during a workshop on "trap-neuter-return," a method of managing the stray and feral cat population that Chernoff was known to use.
"He wasn't one of the main four we were following, but we were so taken by his warmth and affability when we encountered him at a (trap-neuter-return) workshop that we just knew we had to put him in our film," the post read.
A brief clip from the documentary shows Chernoff showing off his many cat tattoos. He tells the camera that he had a cat as a child.
"I just was always into cats," Chernoff says. "Cats and Harleys and tattoos. That's what I'm into."
Chernoff's Facebook page is filled with photos of his cats, 11 of them, along with photos of his building projects. Motorcycles and military memorabilia are also heavily featured on his page.
Last month, he posted a wedding photo of his parents, along with his Army basic training photo, writing that he had just stumbled upon the pictures. Chernoff was not married and had no immediate family left, according to Philadelphia's Jewish Exponent.
"We tried the best we could to keep him family-oriented because he had no parents, he had no siblings and he had no children," Chernoff's cousin, Beverly Levin, told the Exponent. "He was with us for Rosh Hashanah just last month. We kept him as close as we could because he was alone in the world."
Since his death, friends in the animal rescue community and beyond have mourned Chernoff on social media. They have also contributed more than $18,000 to a GoFundMe page set up by Levin's son, David Levin, to pay for Chernoff's funeral and provide for more cats to be rescued.
"Al's kids were his cats," David Levin wrote on the fundraising page.
A private donor, along with Chernoff's veteran benefits, have taken care of the cost of his funeral and memorial service, which is scheduled for Nov. 24 in Southampton. All the funds raised by the GoFundMe campaign will be distributed to multiple animal rescues, David Levin wrote in an update.
Chernoff's 11 cats, along with three turtles and two frogs, were rescued from his home following his death.
Friend and fellow rescuer Gwen Cooper wrote that she was "shocked and saddened beyond the telling of it" to learn of Chernoff's death.
"Al was a fierce and tireless advocate for rescue cats -- one of the staunchest protectors of cats I've ever known -- and I was honored and privileged to count him among my personal friends in rescue for many years," Cooper wrote. "My heart goes out to the people and felines who knew and loved him best."
She said she was certain the "veritable army of cats" he saved over the years were there to greet him on the "rainbow bridge" when he died.
Chernoff was also active in the Jewish war veterans' community, the Exponent reported.
"He went out of his way many a time for people who suffered what used to be called shell shock and what is now called PTSD (post-traumatic stress disorder)," M.B. Kanis, commander of the Jewish War Veterans Drizin-Weiss Post 215, told the publication. "He recognized PTSD and knew that people with service animals could become more calm and relaxed and more focused. In the Philadelphia area, I know of at least three service veterans who he helped hands-on (with service animals)."
Emily Petry, who described Chernoff as the "best cat daddy ever," said he was one of the kindest people she'd ever known.
"Nobody who ever knew you would have ever done you any harm," Petry wrote.
Ashley Foresta, a fellow animal rescuer in Philadelphia, told the Daily Mail she could not imagine why the 14-year-old suspect was in Chernoff's house. Foresta speculated that perhaps Chernoff had hired the girl to clean his home, but Branconi told the Mail he had never seen the girl at the duplex before.
"I just can't imagine for one minute that Al was the type of person who would have had an inappropriate relationship with a 14-year-old girl -- but at the same time I can't think of anyone ever having a reason to kill him," Foresta said.
"To be honest, maybe part of me doesn't want to know the whole truth," she said.
Chernoff's family and friends weren't the only ones puzzled by his slaying. Coulter said last week that detectives were still piecing together what happened and why.
"Who it is, is identified, but the why and the rationale behind it is what the investigators are now working on," Coulter told reporters. "These things take time to get right.
"I know that everybody would like to have everything answered, and so would we, but we want to make sure that we do it in a way that the judicial process plays out fairly and everybody involved gets justice."