Jackie Arkloev, a naturalised Swede of Liberian origin who is already serving a life sentence in Sweden for killing two police officers, considers himself a new person, the Swedish press reports.
Arkloev's attorney Per Durling has said that his client has pleaded guilty to most charges and is willing to face his past.
Arkloev has been charged in Stockholm with crimes against the laws and customs of war.
A court in Mostar, southern Bosnia-Herzegovina, in 1995 sentenced Arkloev to 15 years in prison for war crimes and the Supreme Court in Sarajevo reduced the sentence to eight years.
After a brief stay in a prison in Zenica near Sarajevo, Arkloev was transferred to Sweden to serve his sentence, but a Swedish court acquitted him due to lack of evidence.
Soon afterwards Arkloev killed two Swedish police officers and was sentenced to life imprisonment. Associated Press has reported that the court renewed proceedings against Arkloev after new witnesses came forward. The retrial, which started on Friday with Arkloev entering a plea of guilty, is expected to be completed next month.
The media have reported that Arkloev is charged with participation in war crimes committed in 1993 against Bosnian prisoners in the Croat-run prison camps Heliodrom and Dretelj near Mostar.