Gjert Ingebrigtsen, the father of Olympic 1500m champion Jakob, has been charged by Norwegian police with physical abuse.
Last year, Jakob, 23, and his older brothers Henrik 33, and Filip, 31, who are also Olympic athletes, made public claims that their father, who had coached them until 2022, had been violent.
The 58-year-old has strenuously denied the allegations.
Police in Norway, who had been investigating the case, said on Monday that Gjert had been charged with one offence.
Norwegian website VG, which published the initial story with the brothers, said the victim, external, who was allegedly beaten with a wet towel on one occasion, was not one of the three siblings but a younger family member.
The remaining cases against Gjert have been dropped – five on the strength of evidence and one because of time constraints.
Mette Yvonne Larsen, who represents five of the Ingebrigtsen children, told VG they would appeal against at least one of the dropped cases.
In October, the brothers, who are among seven Ingebrigtsen children, wrote that they still felt discomfort and fear about Gjert and had to tell their story publicly because of intense media coverage in Norway about their split with him.
"We have grown up with a father who has been very aggressive and controlling and who has used physical violence and threats as part of his upbringing,” they said.
"We still feel discomfort and fear which has been in us since childhood.
"Two years ago, the same aggression and physical punishment struck again. It was the drop that made the cup run over."
On Monday, Gjert’s lawyer, John Christian Elden, again maintained his client’s innocence.
“Concerning the dismissed charges, we concur that there is no evidence to suggest that Mr Ingebrigtsen has committed any act punishable by law,” he said in a statement to BBC Sport.
“Moreover, Mr Ingebrigtsen disputes the account of events that form the basis of the indictment and, as such, does not acknowledge any criminal wrongdoing.”
He added they intend to contest the claims “vigorously” in court.
As well as being Olympic champion, Jakob is a two-time 5,000m world champion and is preparing for this summer’s Olympics in Paris while Henrik and Filip were European 1500m champions in 2012 and 2016 respectively.