GUATEMALA CITY (Reuters) -- Prosecutors investigating the slaying last
                  year of a Roman Catholic bishop began running DNA tests on 12 military
                  officers and a priest on Wednesday, hoping science can solve one of
                  Guatemala's most shocking murders.

                  Bishop Juan Jose Gerardi was killed on April 26, 1998, two days after he
                  presented an exhaustive report blaming the military for most human rights
                  violations committed during the country's 36-year civil war.

                  Church officials and human rights activists have accused Guatemala's security
                  forces of masterminding the killing and of hindering the investigation. The
                  military denies any involvement.

                  After a year-long investigation that has failed to produce any culprits, Special
                  Prosecutor Celvin Galindo requested that DNA tests be performed on 12
                  military officers and five other people, including Mario Orantes, the priest
                  who found Gerardi bludgeoned to death in a Guatemala City parish.

                  The DNA tests -- believed to be the first to be performed on members of
                  Guatemala's powerful military -- will be sent on Thursday to the United
                  States, where they will be analysed to see if they match with blood found in
                  the crime scene. Two FBI agents watched as prosecutors sealed the tests.
                  Results will be available in late May.

                  "This is a positive precedent for Guatemala's justice system," Ronalth
                  Ochaeta, director of the Guatemalan Archbishopric's Human Rights Office
                  told reporters.

                  Human rights activists have said the 75-year-old bishop's death has become
                  a major test in Guatemala's bid to end decades of impunity by the military
                  and consolidate peace in this country of 11 million.

                  The war killed 200,000 people and ended in 1996 with a peace accord
                  signed between the government and Marxist rebels.