"There has been scarce political will to provide a fair solution," Napolitano said. "The malfunctioning of the Indian justices system (shows that this problem) is not just an Italian one," the Italian news agency ANSA quoted the President as saying.
He also said that he will meet Premier Matteo Renzi tomorrow to discuss the case.
"I'm counting on having a meeting tomorrow morning with Renzi, who will give me the latest developments on the steps taken with respect to the Indian authorities," he said.
Latorre had flown to Italy after suffering a stroke-like attack earlier this year.
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The two Italian marines, accused of killing two fishermen in Kerala in 2012, maintain that they fired at them after mistaking them for pirates while guarding an Italian oil tanker.
The marines had been living in the Italian embassy in New Delhi since then waiting to be tried, and were not supposed to leave the country.
Meanwhile, Italian Foreign Minister Paolo Gentiloni has told State broadcaster RAI here that "The harvest (from the dialogue with India) has been very disappointing. If the agreement is what we saw the other day, then we're not going very far. I hope that different roads can be found in the next few days.