The Norwegian who admitted to the Oslo bombing and Utoya island massacre that killed 77 people had traces of drugs in his blood at the time of his arrest.

Samples were taken from Anders Behring Breivik after his arrest on July 22, his lawyer said on Sunday.

"The results are not complete but he (Breivik) has said he took a cocktail of medicines," Geir Lippestad told the VG newspaper.

Prosecutor Christian Hatlo on Saturday told broadcaster NRK that blood tests taken after Breivik's arrest on July 22 indicated his client had taken some form of drugs. He did not offer details.

Hatlo also said police were becoming increasingly convinced Breivik carried out the attacks alone, as the 32-year-old has stated.

As the days pass we are more and more certain he managed to carry out the attacks alone," Hatlo told Sunday's edition of the Aftenposten daily, saying Breivik's explanations seemed to tally.

Police have questioned Breivik about how he made the bomb and about the vehicles he used in the car bomb and to drive to Utoya.

Anders Behring Breivik has admitted carrying out a massacre on an island, a venue for a Labour Party youth camp, and a bombing in the capital Oslo. But he has refused to accept criminal responsibility for them, saying that his actions were "gruesome, but necessary".

The death toll from Breivik's horrific crimes rose to 77 last weekend after a body was found in the water off the isle of Utoya a week after his gun rampage there.

We need your support so Novinite.com can keep delivering news and information about Bulgaria! Thank you!