Nearly a century after they perished aboard the luxury liner Titanic, three mystery passengers who were laid to rest in unmarked graves -- including a two-year-old baby boy -- may finally be identified by Canadian researchers through DNA testing. Scientists will partially exhume the remains of a woman in her 30s, a young man and a baby, whose graves in Halifax, Nova Scotia, are marked simply No. 281, No. 240, and No. 4., in a bid to match bone fragments to extended family members who instigated the project. "We're looking at this as scientists and we're really going to be looking at the quality of the bone," said Alan Ruffman, a marine geophysicist in Halifax.