A Chilean judge isn't ready to close the probe into the mysterious death of Chilean Nobel Prize-winning poet Pablo Neruda four decades ago.

Chile's medical legal service said Friday that the judge investigating the case has requested more tests for substances that were not found during a first round of investigations.

Forensic tests last year revealed no suspicious chemical agents in Neruda's bones. But his family and driver were not satisfied and requested more proof.

Neruda died during the chaos that followed Chile's 1973 military coup. The official version is that the poet died of cancer. But Neruda's former driver has said for years that agents of the dictatorship injected poison into the leftist poet's stomach while he was bedridden at the Santa Maria clinic in Santiago.