On Monday, Army officials released a detailed timeline of Specialist Ivan Lopez’s eight-minute shooting spree, which left three soldiers dead and 16 other people wounded. Investigators have not yet definitively settled on a motive for Lopez’s actions, however.

"We have not confirmed a definitive motive, but are doing everything possible to do so. We are considering all credible information and evidence to include social and digital media aspects of the case," U.S. Army Criminal Investigation Command spokesman Chris Grey said. He added, "We have not uncovered any history of criminal convictions or previous criminal activity by Specialist Lopez." The best inference currently is that Lopez was frustrated over a leave of absence he had requested.

According to the Army’s official timeline, Lopez initially opened fire at the 49th Transportation Battalion Headquarters (circled in red above), killing one soldier and wounding 10. He then got into his vehicle and slowly proceeded down 73rd Street (yellow circle), firing at two soldiers and wounding one of them. He then entered the Motor Pool Office (green circle), shooting one soldier and wounding two others. Afterwards, driving back down Motor Pool Road, he fired at another vehicle (blue rectangle), wounding one passenger. Lopez then headed to the Medical Brigade Headquarters (blue circle), wounding one soldier outside, and killing one soldier inside and wounding another. Finally, he drove to a parking lot (purple circle) where, upon being fired upon by Fort Hood Police, he turned his .45 caliber handgun on himself.

President Obama and First Lady Michelle Obama will attend a memorial service for the three soldiers killed in the attack on Wednesday,