Aaron Alexis, the alleged gunman who killed 12 people including an Indian American inside a heavily guarded Washington Navy Yard on Monday, had a history of mental illness, law enforcement officials have said.
"Initial reports indicate that this is an individual who may have had some mental health problems," US President Barack Obama told the Spanish-language network Telemundo.
"The fact that we do not have a firm enough background check system is something that makes us more vulnerable to these kinds of mass shootings," he said in an apparent reference to America’s lax gun control laws.
According to the Federal Bureau of Investigation, which is studying the mental history of the alleged shooter, the Rhode Island military base had received report from the Newport Police Department that Alexis was hearing voices.
FBI Assistant Director in Charge Valerie Parlave told reporters that at this time, they believe that deceased shooter, Aaron Alexis, acted alone.
Even as federal agencies continue with their investigations, Parlave said Alexis is believed to have entered Building 197 at the Navy Yard with a shotgun.
"We believe Alexis may have gained access to a handgun once inside the facility and after he began shooting. Alexis had legitimate access to the Navy Yard as a result of his work as a contractor, and he utilised a valid pass to gain entry to the building," she said.
"We also continue to conduct all other necessary investigation to learn about the activities and contacts of Alexis. We continue to conduct interviews, exploit digital media, and run down every lead we can to piece together his recent movements and to determine the motive behind this attack. We can say that we have determined that Alexis arrived in the Washington area on or about August 25, and he has stayed at local hotels in the area since that time," she said.
"Most recently, he is known to have stayed at a Residence Inn in Southwest Washington, starting on September 7," Parlave said.
However, she did not mention the motivation of the shooter.
"We continue to look into Alexis' past, including his medical and criminal histories," Parlave added.
Image: A police handout photo of Aaron Alexis ' Photograph: Reuters