Oklahoma Bombing (1995 Bombing of Alfred P. Murrah Building)

At 9:02 a.m. on April 19, 1995, a powerful truck bomb exploded on the street in front of the Alfred P. Murrah Federal Building, a U.S. government complex in Oklahoma City, Oklahoma. The explosion caused enormous damage, completely destroying a third of the seven-story building, including a day care center on the first floor near the front, and damaging more than three hundred buildings in the vicinity. The bomb killed 168 people, including 19 children and one rescue worker. It injured over 800 others, some of them blocks away, as the explosion turned street signs, shards of glass , and other debris into missiles and blew pedestrians off their feet. It was the largest domestic terror attack in U.S. history and the largest terrorist attack on U.S. soil until the attacks of September 11, 2001.

Less than an hour later, an Oklahoma highway patrolman stopped and arrested Gulf War veteran Timothy McVeigh for driving without a license plate and carrying a concealed weapon, a 9 mm Glock handgun. While McVeigh was being taken to the jail in Perry, Oklahoma, he left behind in the police cruiser a business card for Paulson's Military Supply. On the back McVeigh had written "TNT $5/stick need more" and "Call after 01 May, see if I can get some more." This would be the first piece of physical evidence that would implicate McVeigh in the bombing.

While McVeigh awaited his bail hearing for the traffic and concealed weapon charges, the investigation of the bombing in Oklahoma proceeded. Many experts and members of the public initially assumed that the bombing was the work of foreign terrorists, but at the FBI's behavioral sciences unit in Virginia, psychological profiler Clinton R. Van Zandt arrived at a different conclusion. Noting that the bombing occurred on the two-year anniversary of the Branch Davidian siege in Waco, Texas—a day of infamy among right-wing militia and antigovernment groups—he concluded that the bomber was probably a white male in his twenties, a military veteran, and a member of a militia group.

As events turned out, this profile closely fit Timothy McVeigh. From an early age he had been fascinated with weapons. In 1988, he joined the U.S. Army, and he served with distinction as a gunner in the Gulf War in Iraq, earning a Bronze Star. When he failed in his effort to become a Green Beret, he left the army and became increasingly paranoid about what he saw as the oppressiveness of the U.S. government, particularly its efforts to curb the spread of guns, which McVeigh saw as a violation of the "right to bear arms" guaranteed by the Second Amendment of the Constitution. His antigovernment rage reached a boiling point in 1993 with the events in Waco. That siege, based on the government's belief that the cult's leader, David Koresh, had a cache of illegal weapons, had begun on February 28, 1993. It ended on April 19 when federal agents stormed Koresh's compound, a fire erupted, and seventy-five people inside were killed.

Enlisting the aid of army companions Terry Nichols and Michael Fortier, McVeigh decided to take action against the government. He had long admired the book The Turner Diaries, written by American Nazi leader and white supremacist William L. Pierce under the name Andrew Macdonald. In this book, the protagonist Earl Turner blows up an FBI building in Washington, D.C., with a truck bomb. McVeigh's goal was to wreak vengeance in similar fashion against the Bureau of Alcohol, Tobacco, and Firearms (ATF ) for its role in the events in Waco. As it turned out, McVeigh's choice of target was a mistake, for the ATF did not maintain an office in the Murrah building.

Evidence that McVeigh was behind the bombing quickly accumulated. The bomb was contained in a yellow Ryder rental truck. The truck's 250-pound rear axle, which had landed on a car near the scene of the bombing, had an identifying number, and the rear bumper, license plate intact and legible, was found nearby. The truck was traced to a Ryder rental agency in Junction City, where the rental agreement had been signed by a "Robert Kling." Employees at the agency helped an FBI artist create a sketch of Kling, referred to as John Doe #1; they also created a sketch of another man who was in the agency at the same time, John Doe #2, although this person was never found or identified. Investigators showed the pictures throughout the area. That evening, the manager of a local motel told investigators that she recognized John Doe #1 and that he had registered at the motel under the name Timothy McVeigh. Additionally, McVeigh had parked a yellow Ryder truck in the motel's parking lot two nights before the bombing.

Later investigation would piece together the actions of McVeigh and Nichols in the weeks and months before the bombing. Following the advice of various bomb-building manuals, they gathered and stored their materials. Forensic examination of the bombsite showed the bomb consisted primarily of ammonium nitrate, an agricultural fertilizer, and nitromethane, a volatile motor-racing fuel. Experts estimate that the size of the bomb ranged from 4,000–5,000 pounds and detonated with an initial explosive force of 500,000 pounds per square inch. Traces of these chemicals were found on McVeigh's clothing, as well as on the victims. Shortly before 9:00 on the morning of April 19, McVeigh drove the truck to the street outside the Murrah building and walked away. Minutes later, the bomb detonated. Some experts argued that the pattern of the bomb blast and the amount of damage suggest more than one bomb, but these views were not widely accepted.

McVeigh was arrested for the bombing while still in jail on the traffic and gun charges. His trial began in Denver, Colorado, on April 24, 1997. Damaging testimony was offered by Fortier, as well as by Fortier's wife, Lori, and McVeigh's sister Jennifer, all of whom knew details of the plot. Physical evidence included not only the Ryder truck parts and the bomb residue on McVeigh's clothing but also his fingerprints on receipts from his purchase of the bomb's materials and calling-card records that tracked his movements. McVeigh was found guilty and executed on June 11, 2001. Nichols was later sentenced to life in prison, and Michael Fortier was sentenced to twelve years in prison for failing to warn authorities of the attack.

Although forensic science played a role in the investigation of the bombing, its chief role was in victim identification . Some of the bodies were complete enough to allow for fingerprint identification, but many were fragmented, making the work of identification painstaking and arduous. The forensic investigators' first step was to gather antemortem information, including lists of people who were believed to be at or near the bombsite. Families and funeral directors provided demographic information, and potential victims' dentists were contacted to provide records. As each body was brought to a temporary morgue across the street from the Murrah building, the task of postmortem information gathering began. A prominent role was played by forensic odontologists, who faced the grim task of identifying the remains of the victims from teeth. They estimated the age of children based on patterns of primary and permanent teeth. Many of these children had pieces of wallboard embedded in their teeth, suggesting that the explosion had blown them through the wall of the day care center.

Radiologists also played a key role. After a body was discovered, an average of fifteen x rays of it were taken. Pathologists, anthropologists, and FBI bomb specialists examined these x rays to identify the victims as well as to uncover crime scene evidence. In many cases, the x rays revealed either healed fractures or degenerative conditions. One victim, for example, was identified from degenerative changes in the spine; another was identified from healed fractures in the tibia and fibula. X rays of missing persons who were thought to be victims of the bombing were compared with these postmortem x rays for possible matches. X rays also revealed the presence of foreign objects in the bodies, including evidence of the bomb itself, and they were used to distinguish bomb evidence from leaded-glass shards from the building's windows.

Finally, forensic anthropologists also played a key role in victim identification. In many instances, only a single disembodied body part was found, and body parts were often commingled. Forensic anthropologists could, for example, measure a limb, then use a computer program that determines age and race from bone measurements to pin down the demographics of the victim, which could then be compared with antemortem information to provide a possible match. This procedure sometimes had to be used in tandem with other methods. In one instance, a forensic anthropologist identified a lower leg as belonging to a white male about 30 years of age. Because the leg had two pairs of socks, a military boot, and blousing straps, the question arose as to whether a second bomber may have been present and killed in the explosion. The leg, however, underwent DNA testing, which contradicted the earlier results, showing that it came from a twenty-one-year-old African American woman. This instance showed that forensic anthropologists often cannot rely on a single method of identification, but may have to use two or more methods to achieve a positive identification.

By the time all of the victims had been identified three weeks after the explosion, forty-four had been identified through teeth alone; twenty-five through fingerprints alone; seventy-seven through a combination of teeth and fingerprints; one through teeth and palm prints; one through teeth, fingerprints, and DNA; six through x rays alone; four through palm prints; three through DNA alone; one through footprints; one through a toe print; one through marks and scars; and four through visual identification.

see also Anthropology; Bomb (explosion) investigations; Explosives; Odontology; Osteology and skeletal radiology; Profiling; Psychological profile.