According to the Houston Police Department, the shooting happened on Harwin Drive in the Sharpstown area at about 2 a.m.
Police said it all happened as two officers were pulling over someone, and during that traffic stop, the officers reportedly saw a man start shooting toward a group of people in the alleyway.
HPD said the stop had nothing to do with the shooting -- that the officers just happened to see it unfold.
The department said an officer shot five times toward the guy who was shooting, but he wasn't hit.
"While these officers were on the traffic stop, back in the back of the alley, there is a kind of a homeless encampment back there. They see one male distance from the group, and start shooting toward the group of people. One of our officers shoots five times toward that individual that's shooting at people. He only shot five times, gets on the air -- everybody, you know, when that happens people start running," HPD Lt. R Willkens said.
Authorities said three people were shot, including a 28-year-old pregnant woman, a 35-year-old man, and a 57-year-old man.
They were all reportedly taken to the hospital.
Police said they are investigating whether the victims were hit by the shooting suspect or the officer's gunfire.
As for the suspect, Willkens said they do have a man in custody who they believe is the shooter, but they have not released any information on him yet.
Police said they found the pistol the man used along with the holster. An ABC13 camera crew captured several shell casings at the scene.
HPD said an investigation into the shooting is ongoing.