American Murder: The Family Next Door is the latest true-crime documentary hit for Netflix.
Billed by viewers as "one of the hardest things" available to watch on the streaming service, the documentary tells the story of Shanann Watts, who was murdered by her husband, Chris Watts in 2018.
He also killed their two daughters, aged three and four.
Shanann's brother, Frankie Rzucek, has now shared his verdict on Facebook, praising director Jenny Popplewell for "giving [his] sister a voice".
"I highly recommend watching this," he wrote, giving it his seal of approval. "The director made sure we were a part of the whole process and we met the whole team personally."
He revealed that the team behind the doc "made sure we were okay with them making it" before production began.
"It also shows what her life was like before he came along and how happy she was with her beautiful family until he cheated and turned into a different person and became that monster," Rzucek added.
He also expressed shock over the fact that Kylie Jenner had watched the documentary.
“How crazy that even Kylie Jenner watched it and shared this on her Instagram," he wrote, hailing his sister as “an inspiration to millions of people all over the world”.
He added: “I’m honoured to be her little brother. She's still changing lives and I couldn't be more proud.”
Meanwhile, his sister’s killer is said to be in “anguish” upon learning the documentary was released on Netflix.
American Murder has been praised for “using raw, firsthand footage” including bodycam clips of police's visits to the family home in the wake of Shan’ann's disappearance.
However, this footage has led to many viewers feeling disturbed, with one going so far as to say the film left them “broken”.
It is currently the most viewed title on Netflix.
