Four people are dead and sixteen people were left wounded, some critically, after a lone gunman opened fire at Fort Hood in Texas late Wednesday afternoon. The alleged shooter is among the dead, according to officials.

Identified as Ivan Lopez, an Army veteran of the Iraq War and said to be suffering from post-traumatic stress disorder (PTSD), the man killed three people and injured more than a dozen others with a semi-automatic handgun before turning the weapon on himself.

According to the Guardian, Lopez

apparently walked into a building on Wednesday and began firing a .45-calibre semi-automatic pistol that had been purchased recently. He then got into a vehicle and continued firing before entering another building and kept shooting.

He was eventually confronted by military police in a parking lot. As he came within 20ft (6 metres) of an officer, the gunman put his hands up but then reached under his jacket and pulled out his weapon. The officer drew her own gun, and the suspect put his pistol to his head and pulled the trigger.

The gunman, who was married and served in Iraq for four months in 2011, had sought help for depression, anxiety and other problems. Before the attack he had been undergoing an assessment to determine whether he had post-traumatic stress disorder, according to Lieutenant General Mark Milley, the senior officer on the base.

Milley said the incident began about 4pm local time (10pm BST) at an administration building for a medical brigade.

Back in 2009, Fort Hood was the scene of another mass shooting when Army psychiatrist Nidal Hasan opened fire on his fellow soldiers, killing thirteen people and wounding 30. Hasan was injured in the attack and is now on death row at Leavenworth Prison.

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