By Carmelo Camilli
POZZUOLI, Italy (Reuters) - Thousands of people packed into a sports hall in the southern town of Pozzuoli on Tuesday to commemorate 38 people who died when a coach plunged 25 meters (80 ft) off a motorway viaduct in one of the worst road accidents in Italian history.
Prime Minister Enrico Letta was among an estimated 4,000 mourners at the service during a day of national mourning called after the accident, which occurred on Sunday night as the coach was returning from an excursion.
"This tragedy has hit everyone. It was a punch to our hearts and affected all of the city," said Salvatore Gritti, who lost a friend in the crash.
Many of the victims, including numerous young children, came from Pozzuoli, just outside the southern city of Naples, and many were related, adding to the sense of loss in the sweltering hall where the funeral was held.
"I had two nieces with their respective husbands (who died) plus four others who were injured," said Luciano Ariello.
"The daughter of my niece with her husband and two children (were injured). Now they are in hospital. I just don't know how they are but at least they are alive," he said.
Prosecutors have opened an investigation into the accident focusing on suspicions of manslaughter, but no charges have been laid and no clear indications have yet emerged as to what may have caused the crash.
An autopsy has been ordered on the body of the driver, who died in the accident, and investigators have also been examining the wreckage of the bus for evidence of possible mechanical failure, as well as the guard rails the coach broke through as it plunged off the road.
The disaster came just days after 79 people were killed in a high speed train crash in Spain, for which the 52 year-old driver has been charged with negligent homicide.
As the formal period of mourning began, Italian newspapers attempted to reconstruct the last minutes before the crash, during which the coach was seen travelling at high speed down the A16 highway near Naples despite clearly marked speed limits.
The coach hit a number of cars and numerous witnesses have reported seeing damage to the bodywork of the vehicle and an open or missing back door, suggesting the driver was having trouble controlling the bus before the crash.
(Writing By James Mackenzie, editing by Gareth Jones)