FORT WORTH, Texas (AP) -- Fort Hood did not have a system in place that could have anticipated a deadly rampage last April that left four soldiers dead and 16 wounded, according to a U.S. Army report released Friday.

There were no clear warnings that Spc. Ivan Lopez would go on a two-block shooting spree before killing himself on April 2, the report released Friday concluded. It also said Lopez's supervisors would have had difficulty recognizing any personal problems leading up to the attack.

Army Spc. Ivan Lopez killed three people and wounded 16 others before killing himself at Fort Hood, Texas, April 2, 2014. (AP Photo/Courtesy of Glidden Lopez)

The report also found that no single factor prompted the incident, despite Army investigators' previous findings that Lopez had been in an argument after being denied leave.

Investigators have said the 34-year-old Iraq War veteran was undergoing treatment for depression and anxiety while being evaluated for post-traumatic stress disorder, but was not considered "likely" to commit violence. He had recently lost two family members, faced financial difficulties and was denied leave to travel to his native Puerto Rico, investigators noted in April.

Risk assessment at Fort Hood relies on self-reporting, the report said, adding that that Lopez could sometimes be "misleading or deceptive." Recommendations in the report included exploring whether soldiers should register privately owned weapons with their commanders.

The Army previously said it was logistically impossible to stop and search all 80,000 people who work on the sprawling base every day.

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