While searching some cases, I found that there are several cases that were badly reported.
I made a list of those cases:
Thomas Speer: Thomas Speer was an African-American preacher who poisoned five members of his family, one of them fatally, near Milner, Georgia, United States on October 7, 1895.
That morning Speer apparently laced coffee with poison, because his wife had refused to pay court costs and a fine for him with her money. He then went off to work on a plantation, while his wife and four children ate breakfast, after which they became sick. Speer was arrested, when his wife accused him of poisoning them. He was charged with murder, since one of his victims, an infant, died.
Early reports indicated that he had fatally poisoned eight or nine of his children out of jealousy, while his wife was out of the house.
John Halton: John Halton (also reported as Joseph Halson) was an American who reportedly killed his wife and seven children half a mile from Ironosa, near San Augustine, Texas, United States on April 29, 1893. Halton, who had been insane for several years, afterwards shot himself in his home.
According to the reports in The Galveston Daily News about the incident these stories are without foundation. While it is true that Halton, who had been in a state of dementia for seven months, locked himself in his home, and committed suicide by shooting himself in the head with a shotgun, his wife and seven children became alarmed about his behaviour and fled the scene. Initially their whereabouts were unknown, probably giving rise to the suspicion that they may have been dead as well, but they were found unharmed a while later.
Paul Beetz:Paul Beetz was a German labourer who killed one person in Berlin, German Reich on January 1, 1922, before being shot by police. He died of his wounds in hospital on January 9.
Some international newspapers reported Beetz had stabbed five women and seven men, but according to the coverage in the local press there is absolutely no indication that there were any other victims than officer Rosengart and Miss Scheppe.
Luxembourg massacre: In March 1901 a Luxembourgian supposedly killed seven people and wounded many others in Luxembourg. The man reportedly ran along a crowded street and struck down several children, shouting that he wanted to save them from the pain of living, until he was shot dead by the father of one of his victims.
The fact that apparently only a few American and Canadian newspapers reported about the crime, all of them printing almost verbatim the same article, while no trace of it could be found in European, including Luxembourgian newspapers, strongly suggests that the story was a hoax.
Do you know more?
Subject: Badly reported cases 
Wed Aug 28, 2019 5:24 pm