Authorities in Italy are investigating why a Swiss-registered light aircraft crashed into a skyscraper in the northern city of Milan.
The crash killed three people - including the pilot - and left dozens of people injured. It was initially feared to be the work of terrorists, sparking memories of the September 11 attacks in the United States.
Officials in Milan said on Friday that 11 people remained in hospital - two of them in a serious condition.
Italian authorities said the pilot, who police named as 67-year-old Luigi-Gino Fasulo from the Swiss town of Pregassona, seemed to have trouble with his landing gear and veered off course shortly before the plane ploughed into the 30-storey Pirelli building on Thursday night.
The 1950s building is home to the local regional government, providing offices for 1,750 people. However, the top five floors of the offices were nearly empty at the time of the accident as they were being renovated.
Rescue worker, Carlo Lio, said it was a stroke of luck that more people were not killed when the 27th floor collapsed onto the 26th floor.
Fasulo took off in his single-engine Commander 112 propeller-driven aircraft shortly after 5pm from Locarno airport in Switzerland.
He is reported to have contacted air traffic controller at Milan's Linate airport some 30 minutes later, saying he was having problems with the plane's landing gear.
The airport told him to fly west, however, for some reason Fasulo headed north towards the city, saying he was resolving the problem.
According to Italy's La Repubblica newspaper, Italian police have travelled to Switzerland to interview Fasulo's friends and relatives following speculation that he might have deliberately crashed the plane.
However, his nephew, Luigi Fasulo, said there was no question his uncle, who had some 30 years flying experience, would have taken his own life.
"My uncle didn't have any financial or health problems. Everyone who knew him would testify that he loved life," the nephew told Italian state television.
The crash was the second air accident to hit Milan in seven months. In October last year, a Scandinavian SAS plane collided with a small private plane on the runway in Linate, killing 118 people.
swissinfo with agencies