According to the Montgomery County Sheriff's Office, Ronald Wayne Schubert, 63, was arrested after shooting and killing the man in the area of Sawdust Road near the North Freeway just before 5 a.m. Friday.
The sheriff's office said a deputy was in the area when the victim was running around exhibiting abnormal behavior.
The deputy was trying to get the man's attention as Schubert attempted to help, the sheriff's office said.
Deputies state the victim charged at Schubert and started attacking him. Schubert was knocked to the ground.
The deputy used a Taser on the victim to no effect. That was when a second deputy arrived and commanded the victim to get on the ground.
The second deputy also used a Taser to limited effect, deputies said.
As deputies continued to command the victim to stop, Schubert opened fire while on the ground, hitting the victim twice, according to deputies.
The victim, whose identity was not immediately disclosed, died at the scene.
The incident is under investigation. The case is expected to be presented to a grand jury for charges.
@MCTXSheriff can confirm a fatal shooting of a male by a security guard that occurred about 4:50 am in the 120 block of Sawdust Rd in Spring, TX. The incident is under investigation. At this time, the security guard is in custody. Details will be released as they are available. pic.twitter.com/7Q6MQvfO5d— MCTXSheriff (@MCTXSheriff) July 24, 2020