LONDON (AP) — He was one of history's most famous explorers, and his first-person account of a 19th-century massacre in the heart of Africa helped galvanize Britain to shut down one of the continent's biggest slave markets.But two researchers now say they've uncovered evidence suggesting Dr. David Livingstone may not have told the whole truth.They say they've used spectral imaging technology to decode Livingstone's long-illegible 1871 field diary and found hints his men may have been involved in the atrocity — contrary to his previous claims.Scans and transcripts of the unedited diaries were posted Tuesday to the website of the University of California, Los Angeles.Livingstone's ill-fated expedition through Africa has long fascinated audiences on both sides of the Atlantic.___Online:http://livingstone.library.ucla.edu/1871diary/