by Jose Torres The number of murders committed in the United States has dropped dramatically, but so has the rate at which they are solved. In 1968, police solved 86% of all murders. But by 1994, just 64% of all murders were solved. In 1998, the most recent year for which figures are available, the FBI says the clearance rate stood at 69%. The drop of unsolved cases comes despite a drop in the murder rate from a high of 9.8 per 100,000 in 1991 to 6.3 per 100,000 now. That?s about the same murder rate as in the late 1960s, when almost 9 out of 10 murders were solved. Cases are getting harder to crack, experts say, because more murders today are committed by strangers rather than by spouses or friends. ?The home was once the most likely place for murder to occur,? says James Fox, a criminologist at Northeastern University. ?Now we have taken the home out of homicide. There is a greater distance between victims and offenders, and the greater the distance, the more difficult it is to solve the crime.? Murderers have become more sophisticated. They know more about crime-solving techniques. Robert Ressler, a retired FBI agent, says some murderers have become skilled at destroying DNA evidence. The solution rate is unlikely to improve, Fox says. ?There is no prospect of seeing the clearance rate return to 80%,? he said.