The investigation in the causes of the fatal building blast in the Belgium city of Liege follows several trails, the Belgium TV channel RTL informs.

The authorities' investigation includes human trafficking and other crimes.

RTL showed in their news a witness identified as Chichi Chengiz, who lived in the building next door for 20 years. Chengiz repeated for the broadcast what he had already told the police – that he knew the Bulgarian girls, who used to live in the collapsed building, and they told him the building owner, Mehmet Calik, traveled often to Bulgaria, “bought them” from their parents, and they now belonged to Calik.

“Calik was known for bringing scores of Bulgarians to work in Belgium. Of course, before arriving here they paid him. He was involved in strange things. One of the girls showed me a pornographic movie where she appeared with Calik,” the witness says, adding the girls told him they were forced to do such things because they were hungry in Bulgaria and had no choice since their father sold them.

The Liege police had not officially confirmed Chengiz' account, just that he is a witness.

RTL reports that if his statements prove true, the explosion might not have been just an accident.

Many in the building further question the fact that they did not smell gas despite the fact the building was old and poorly isolated. In order for a gas leak to cause such massive blast, it should have been going on at least for one hour, the report points out.

On Saturday, the Belgium authorities released the names of the 3 Bulgarian citizens, who have died during the explosion.