UPDATE: Official: Fort Hood gunman asked to transfer to another unit(CNN) -- Fort Hood shooter Spc. Ivan Lopez had asked to transfer and had apparently felt some people in his unit had not treated him appropriately, officials said Monday.
By: Barbara Starr, CNN Pentagon Correspondent, CNN
(CNN) -- Fort Hood shooter Spc. Ivan Lopez had asked to transfer and had apparently felt some people in his unit had not treated him appropriately, officials said Monday.
In an effort to determine what led Lopez to shoot fellow soldiers before turning the gun on himself, the Army is not only looking into his mental health history but also investigating his interactions with fellow soldiers in his unit at Fort Hood, according to a U.S. military official directly familiar with the investigation.
Lopez joined the 154 Transportation Company at Fort Hood after arriving at the post in February. But he apparently felt some in the unit had not treated him appropriately, the official said.
Lopez had recently asked to transfer to another unit, claiming he was being taunted and picked on by soldiers in his unit, a senior U.S. official familiar with the investigation told CNN.
The investigation into how he was treated stems from those reports, the military official said. That official also said it is not clear whether members of his unit, including his supervisor, knew of his mental health history or that he was being treated for anxiety and depression.
Officials have confirmed he received some initial mental health treatment at his previous post at Fort Bliss and was prescribed medications there. Medical examiners will now try to determine exactly what medications he took, whether he took them correctly and whether there may have been some interaction between drugs.
Records show Lopez had had regular mental health appointments in recent months. But what is not known, the military official said, is what role, if any, his mental health situation or his medications may have played in his mounting anger and final attack.
Lopez took his own .45-caliber handgun onto the sprawling Army facility and killed three people and wounded 16 more before taking his own life last week.
Three patients are still being treated at Scott & White Memorial Hospital. All three are listed in fair condition and are continuing to improve, the hospital said.
CNN's Pam Brown contributed to this report.