Madeleine McCann: The Hunt for the Prime Suspect had viewers rushing to defend the missing girl's parents as it aired on ITV.
The documentary, shown last night (Thursday, July 23), explored the breakthrough that German police made in June.
What was the Madeleine McCann documentary about?
Last month, investigators revealed they believed Maddie - just three years old when she was taken from her family's hotel room at the Portuguese resort of Praia de Luge in May, 2007 - was now dead.
And they were looking closely at a new prime suspect - a convicted sex offender, Christian Brückner, who was living near the holiday resort at the time of Maddie's disappearance.
The documentary examined claims of failure and missed opportunity in the investigation.
As it aired, a number of people took to social media to voice their conspiracy theories about the case and Maddie's parents, Gerry and Kate McCann, whom they blamed for leaving their children alone.
However, many others rushed to defend the couple.
What did viewers say about Maddie's parents?
One said: "Twitter is full of [bleeps] jumping at the chance to insult #MadeleineMcCann's parents and let us know how much better at parenting they are. Nobody cares. They lost a child, isn't that punishment enough? [bleeping] [bleeps]."
Another tweeted: "#MadeleineMcCann some of the disgusting things people are tweeting. You don't need to blame the parents. I'm sure they blame themselves every waking moment. #BeKind #stophate."
Responding to someone calling it "shocking neglect", a third wrote: "To be fair, they were only a hundred yards away and checked on them every half hour. Hundreds parents are guilty of that and things appears so much safer on hol #MadeleineMcCann."
Someone else said: "So many hypocrites on here. Spent many holidays in the popular holiday resorts over the years. Parents out drinking at night while their kids are tucked up in bed. There but for the grace of God."
A 'devastating mistake'
A fifth ranted: "Everyone is being so [bleeping] arrogant and insensitive. Kate and Gerry made a devastating mistake. Everyone has done something that could have gone wrong. They just had very bad luck. You are all so rude. Show a bit of compassion for [bleeps] sake."
Another, who admitted feeling "appalled" over the tweets, said: "Losing a child is bad enough, not knowing is unimaginable. I'm sure they regret that decision each and every day. Please stop the hate towards them and making them out to be bad parents."
- Madeleine McCann: The Hunt for the Prime Suspect is available to watch now on ITV Hub
What did you think of the documentary? Leave us a comment on our Facebook page @EntertainmentDailyFix and let us know.