Former agent Willie McKay has labelled Cardiff a "disgrace" and claimed the Premier League club "abandoned" the Argentine as he made his own travel arrangements after his £15 million move from Nantes.
McKay's son Mark was Nantes' acting agent in the deal for Sala, who died, along with pilot David Ibbotson, following the plane crash over the English Channel last month.
Willie McKay arranged the travel for Sala, who he claims was left to his own devices in a hotel and required help to sort his travel onwards to Cardiff.
"He was abandoned in a hotel more or less to do his travel arrangements himself," Willie McKay told BBC Sport.
Cardiff have denied any wrongdoing though, insisting their attempts to organise a commercial flight were declined.
A statement read: "Our club was in the process of organising a commercial flight for Mr Sala until this offer was declined owing to separate arrangements being made - the planning and specifics of which Cardiff was not privy to.
"Cardiff has serious concerns over the potential unlawfulness of the journey following information that has been released. Clearly more answers as to the details surrounding this terrible tragedy are required."
Mark McKay now regrets his involvement in the transfer, with his father criticising Cardiff, insisting they "let themselves down badly" in the way they conducted themselves following the transfer.
"Nobody in Cardiff seemed to be doing anything. It was a bit embarrassing for Cardiff," Willie McKay said. "They buy a player for 17m euros and then leave him in a hotel by himself to go on the computer and look for a flight.
"I think Cardiff let themselves down badly. The way they've acted so far, they've been a disgrace."
