Unidentified criminals Wednesday night blasted a grenade inside a house, injuring seven persons – five of them seriously at Kayange in the commune of Rugazi in the province of Bubanza, some 20 km northwest of the Burundian capital Bujumbura, the police commissioner in Bubanza told Xinhua by phone."The grenade blast targeted a household at about 20:00 local time (18:00 GMT) and after firing the grenade through the house window, the attackers ran away. Seven persons were injured and five of them were immediately rushed to hospitals in the capital Bujumbura,” said Remegie Nzeyimana, police commissioner in the province of Bubanza. According to him, the injured include the father of the family, his five children and his daughter-in-law. Nzeyimana said that he visited the attacked household on Thursday to inquire about the circumstances of the attack. "We have already started investigations in the grenade attack and we’re still locating the criminals in a bid to arrest them,” he said.Elsewhere a man and his wife died after a grenade exploded in their bedroom on Tuesday night at Burangwa in the commune of Bugarama in the Burundian western province of Bujumbura Rural, the local African Public Radio (RPA) reported on Wednesday evening. The radio quoted Bugarama Administrator Joachim Manirakiza as saying that the man and his wife were killed over "witchcraft” accusations. "Unidentified attackers blasted a grenade inside the victims’ bedroom after breaking the window and ran away. A baby who was sleeping in the parents’ bedroom was however unharmed,” RPA quoted the local authority as saying. Joachim Manirakiza said that the police are busy trying to locate the criminals and urged residents to hand over illegally kept weapons to the police or the army.