French investigators were on Monday investigating the death of a Tongan rugby player who died from an apparent heart attack during a French third division match on Sunday, judicial sources said.

The investigators were undertaking a forensic investigation to determine the possible presence of any toxic compounds in the body 28-year-old Perigueux flanker Feao Latu, who collapsed barely 15 minutes into his side's top-of-the-table match at Cahors.

The sources said the results of the tests would be known on Tuesday and would be followed on a decision on the possible need for an autopsy.

Latu was pronounced dead in hospital following 45 minutes of emergency treatment pitchside.

Latu, who had recently married and was the father of two young children, had complained of feeling unwell in the 17th minute when Cahors had scored a try.

While the players waited for the conversion, Latu fell to his knees and signalled to the bench and the club doctor for attention.

Around a thousand spectators witnessed the drama at the Lucien Desprats stadium in Cahors with the match eventually called off.

Teammate Dorian Kenil, a lock forward, was stunned by his friend's death, saying Sunday: "It's incomprehensible, we can't believe it, everyone is saying it's not possible."

Another Perigueux player Francis Rongieras died in similar tragic circumstances 18 years ago.

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