Two more people have been arrested in connection with the tragic incident in the southern Bulgarian town of Krumovgrad, where an improvised bomb killed three youngsters at a children's home.

This brings the number of detentions following Saturday’s incident, to six. One of the latest to be arrested is the son of the heating maintenance engineer at the home, and the other has been described as a friend of his.

An arsenal of various explosives has been discovered at their home. Investigators have been trying to establish the reason for keeping them there.

The director of the social home, Svetoslav Dayov, was detained last night for 24 hours, but this period will be extended for a further 72 hours, according to the regional prosecutor Svetozar Lazaro, as he is charged with causing death by negligence of more than one person.

The others already arrested are two female supervisors at the home and the stoker Hamdi, who had earlier tried to commit suicide.

Hamdi was taken to hospital in Kardjali and was in a stable condition, after stabbing himself in the stomach with a pocket knife.

Earlier today, Minister of Labor and Social Policy Totyu Mladenov had said that there was evidence that Hamdi had given the children some small things which they had taken into the home.

It was also known that he had friendly relations with the three teenagers, who had often helped him, and to whom he had paid small sums of money, he said.

"Control in the home is not bad. We will send letters to all mayors in the country to improve the control of those who enter into those homes," he emphasized.

The small town of Krumovgrad is in shock after Saturday’s tragedy in which one youth died on the spot and two others died of serious injuries hospital.

The three have been named as Dzhingiz Rushen (13), Sunay Keazim (16), and Dzhingiz Dzhemal (15).

Once autopsies have been completed, a week of mourning will be declared in Krumovgrad.