Saad al-Hilli, who was shot dead in his car last month along with his wife, her mother, and a passing French cyclist, is believed to have gone to Geneva shortly before the massacre, the Tribune de Geneve daily reported in its online edition.
The paper said it had obtained information that Hilli's trip to Geneva, "as well as the seized money are linked to the murders."
On September 5th, 50-year-old Hilli, his 47-year-old wife Iqbal and her 74-year-old mother Suhaila al-Allaf, who held a Swedish passport, were shot dead in a forest car park near the village of Chevaline, not far from Annecy, where they were vacationing.
Frenchman Sylvain Mollier, a passing cyclist, was also shot and killed, while the couple's two young daughters survived the attack, although the elder girl was seriously injured.
Swiss public broadcaster RTS meanwhile reported on Friday that the bank account seized in Geneva had belonged to Hilli's recently deceased father and that it contained "well under" the six million francs (five million euros) evoked by British media.
Investigators have, among other leads, looked into a possible falling-out between Hilli and his brother, living in Britain, over the inheritance from their father, who recently died in Spain.
Hilli's father left behind an estate and cash worth millions of euros, according to British media reports.
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Geneva prosecutor Dario Zanni is meanwhile taking part in the investigation following a request from French authorities, his office told AFP Friday, refusing to divulge further information.
In addition to the reported Swiss bank account link to the crime, French investigators have said they were looking into whether the killer may have fled across the nearby Swiss border after the murders.