The person was freed on Thursday afternoon, Annecy prosecutor Line Bonnet tweeted.
“The explanations given and the verifications carried out made it possible to rule out their potential participation in the events,” the prosecutor wrote in a press release.
She added that “investigations are continuing to identify the perpetrator(s)”.
[communiqué de presse]
Levée de garde à vue par le juge d’instruction #Chevaline 🔴Aucune charge n’est retenue contre la personne gardée à vue. Les investigations se poursuivent pour identifier le ou les auteurs. pic.twitter.com/Br2lycP8pR
— Procureure Annecy (@ProcAnnecy) January 13, 2022
Nine years into the investigation, no charges have been filed in the case.
The former suspect, who was arrested on Wednesday morning, was the same motorcyclist who was already interrogated over the killings in 2015, French media reported.
At the time, he was arrested after police circulated a sketch of a biker seen near the crime scene, but investigators found no evidence to implicate him then either.
Saad al-Hilli, 50, his wife, Ikbal, 47, and her mother Suhaila al-Allaf, 74, were shot dead on a road near Annecy in eastern France on September 5 2012.
Their two young daughters survived the horror, but 45-year-old cyclist Sylvain Mollier was also killed.
After his rearrest, the former suspect’s custody was extended by prosecutors late on Wednesday as they worked to “verify the timeline”, Ms Bonnet said.
His defence lawyer, Jean-Christophe Basson-Larbi, was quoted by French broadcaster BFMTV as saying that the renewed questioning was down to a “judicial error” and that his client was living through a “nightmare”.
A photofit of a motorcyclist in a distinctive helmet seen near the crime scene was issued by police in 2013.
He was arrested two years later, but was released after claiming he had been paragliding in the area.
He said he had not come forward earlier, despite the wide circulation of the sketch, because he had not seen anything and did not think his evidence would be useful, BFMTV reported.
“The gentleman’s position has always been the same: ‘I was walking… but never crossed paths with this poor family’,” Mr Basson-Larbi told journalists of his client, a 57-year-old businessman living in Lyon.
The bodies of Iraqi-born engineer Mr al-Hilli and his dentist wife, who lived in Claygate, Surrey, were discovered along with that of Mrs al-Hilli’s mother in their BMW on a remote forest route.
In a bizarre twist, Mrs al-Hilli’s previous husband, an American dentist named only as James T, died from a heart attack on the same day as the couple, but police said there was no link to the murders.
Suspects previously arrested in connection with the case include an Iraqi prisoner known as Mr S who was claimed to have said he had been offered “a large sum of money” to kill Iraqis living in the UK.
Mr al-Hilli’s brother, Zaid, was also arrested on suspicion of murder in 2013 but was later told he would face no further action after police found there was insufficient evidence to charge him with a crime.