A tragedy occurred in Illinois, USA yesterday Wednesday evening when a young man broke into a house and fatally stabbed four people, possibly members of the same family.

According to the police in Rockford, five other people were injured in the attack, one of them in critical condition.

The victims are a 15-year-old girl, a 63-year-old woman, a 49-year-old man and a 22-year-old man.

Police have arrested a 22-year-old man as a suspect and are questioning him, while the motive for the murderous attack remains unclear so far.

The state sheriff said a young woman with stab wounds to her hands and face, who ran away, was hospitalized and intubated.

Another man, described by Sheriff Caruana as a “good Samaritan,” suffered less serious stab wounds after he tried to intervene to help the woman.

Rockford Police Chief Carla Read said not all of the victims had been stabbed, but added that none had suffered gunshot wounds.

“Words can’t even express my thoughts right now…” she said. “My heart goes out to the families right now as they suffer a loss.”

Rockford resident Ruth Gallagher told CBS her longtime mailman was among the dead, while the US Postal Service confirmed that one mailman was killed.

In a statement, Rockford Mayor Tom McNamara said his heart “breaks for those who lost their lives, their families and our community.”