FARINDOLA, Italy (AP) -- Questions intensified Monday into whether Italian authorities underestimated the risks facing a snowbound mountain hotel hours before an avalanche hit, as rescue crews weighed using heavy equipment to try to reach 23 people in the hotel who are still buried under the snow.

Five days after up to 60,000 tons of snow, rocks and uprooted trees plowed into the Hotel Rigopiano in central Italy, rescue crews were still digging by hand and with shovels and chainsaws to try to find more survivors.

Firefighter spokesman Luca Cari said emergency crews were working with an "operational hypothesis" that the snow might not have reached all parts of the hotel, and that air pockets might still be keeping people alive.

But he said: "We are fighting against time."

"We know we need to work fast, but in relation to an environment that doesn't allow for fast intervention," he said on Sky TG24.

Heavy machinery, including an excavator, has reached the disaster site northeast of Rome but crews hadn"t decided whether to use it, yet given the risk that it could collapse snow and walls on top of the 23 people still underneath.

So far nine people have been pulled out alive from the snow-crusted hotel debris, and the first were released Monday from the Pescara hospital, officials said. Six people are confirmed dead, although one of them remained trapped inside the rubble.

Meanwhile, the investigation intensified into whether local government officials underestimated the threat facing the hotel, which was already covered with two meters of snow, had no phone service and had dwindling gas supplies when a series of earthquakes rocked central Italy on the morning of Jan. 18.

Italian newspapers on Monday reproduced what they said was an email sent by the hotel owner to local and provincial authorities that afternoon asking for help because "the situation has become worrisome."

"The hotel guests are terrorized by the earthquakes and have decided to stay out in the open," Bruno Di Tommaso wrote. "We"ve tried to do everything to keep them calm, but since they can't leave due to the blocked roads, they"re prepared to spend the night in their cars."

Already, the Pescara prefect's office has faced criticism after a local restaurant owner said his calls reporting the avalanche were ignored. Quintino Marcella said he called the office after receiving word from one of his chefs who was vacationing at the Hotel Rigopiano and escaped the avalanche by chance.

The ANSA news agency reported Monday that the prefect's office had called Di Tommaso after receiving the avalanche alarm, but that the hotel owner -- who was in coastal Pescara at the time, not in the hotel -- hadn't heard anything himself, possibly leading officials to underestimate Marcella's report.

The president of the province, Antonio Di Marco, has confirmed he saw an email from Di Tommaso and had arranged for a snowplow to clear the road that night, the ANSA news agency reported. The avalanche, however, hit sometime before 5:40 p.m., when Marcella received the call from his chef.

One aspect of the criminal investigation into the disaster involves discovering where the province's snowplows were being used, news reports said.