Witness in Building Near San Bernardino Shooting Location Says Suspect Left 'Calmly' in SUV

— -- An eyewitness in San Bernardino, California, whose office window faces the Inland Regional Facility told ABC News he witnessed someone "calmly" leaving the scene of today's mass shooting in a dark-colored SUV.

Speaking from his office while it was still on lockdown, Glenn Willwerth said he could hear people screaming and running at the nearby facility after he heard up to 15 shots fired.

“I don’t know if they knew what they were running from," he said.

After an employee informed him of the active shooting scene, Willwerth told ABC News he grabbed his pistol and headed toward the direction of the gunshots.

At least 14 people were killed and another 17 injured when multiple gunman opened fire at the facility for the developmentally disabled, authorities said. Up to three suspects are still at large, police said.

Local and state agencies mobilized planes and helicopters to search for the SUV.

Get real-time updates as this story unfolds. To start, just "star" this story in ABC News' phone app. Download ABC News for iPhone here or ABC News for Android here.