Updated: Sat Apr. 11 2009 11:18:17 AM

CTV.ca News Staff

Officials in L'Aquila, Italy, say they will investigate allegations that Monday's earthquake should not have caused so many buildings in the medieval city to collapse, alleging some were poorly constructed or made of low-grade materials.

Italian engineers and geologists have indicated that structures built with seismic-safety standards should not have buckled during the 6.3-magnitude quake.

L'Aquila prosecutor Alfredo Rossini told Italian media that he has started an investigation into whether anyone can be held criminally responsible for the crumbling buildings.

"We have the duty to verify whether some buildings were really constructed out of sand, as has been indicated from several sources, or in other cases without steel," Rossini was quoted saying in La Repubblica, a daily newspaper in Rome.

Rossini did not name specific buildings that he will include in the probe. However, collapsed buildings, or structures that have been deemed uninhabitable, include a university dormitory and a hospital.

Reports indicate that these buildings were constructed after officials raised construction standards.

Firefighters that had been sifting through debris told Italian state television on Friday evening that some of the reinforced concrete pillars they had removed appeared to be poorly made.

The firefighters said saws will usually break cleanly through a concrete pillar. However, some of the pillars in L'Aquila crumbled to dust after being cut, which indicates that a considerable amount of sand may have been mixed into the cement.

Meanwhile, rescue crews continued to sift through the rubble for missing residents on Saturday. Rescuers pulled another body from a collapsed building, which raised the death toll to 291.

Workers also concentrated their efforts on a local apartment building after rescue dogs reacted while sniffing through debris, indicating that there may be survivors.

But rescuers said that sounds coming from the rubble were less likely to be survivors than water running, an appliance or an animal.

The region was also spared more aftershocks overnight and early Saturday, the first calm night for residents since Monday's quake.

However, seismic activity carried on through the night, but at a level not felt by residents above ground, civil protection officials said.

In another bit of good news, Pope Benedict XVI sent chocolate Easter eggs to children who are among the 24,000 people currently inhabiting tent cities.

Another 15,000 are living in hotels that are outside of the quake zone.

On Friday, a massive funeral service was held for more than 200 earthquake victims.

With files from The Associated Press