The suspect is a white male in his 30s, Gerke said He added that the incident began at a traffic stop.
The chaotic afternoon started at 3:13 p.m. local time.
Authorities also said that the gunman used an assault rifle-type weapon in the attack, but said how Ator weapon was obtained is still under investigation.
There were initial reports of a second shooter, but there has been no confirmation of one, Chief Gerke said. Police said there are "multiple gunshot victims" in West Texas after reports of gunfire on Saturday in the area of Midland and Odessa. Seven people were in critical condition, two in serious condition and two were treated and released, he said.
A spokesman for the Medical Center Hospital in Odessa said it took in 14 victims, but that it was too soon to give details. Police later confirmed both vehicles were used by the same person.
"I do not know anything about the person or the motive", Mr Morales said. Screaming theatre goers ran from the complex. During the confusing moments of the pursuit, authorities thought there might be two shooters firing from two vehicles. "It just all happened so quickly". He said a little girl was bleeding, but she hadn't been shot, and that he later found out she was grazed in the face. "It went through the door of the vehicle and shot him right in his side. his wife was just covered in blood".
The investigation into another mass shooting in Texas is unfolding as a number of looser gun laws in the state took effect Sunday.
After the shooting Saturday, Democratic presidential candidates issued statements calling for gun reform. Odessa is about 32 kilometres southwest of Midland.
"We need to end this epidemic", O'Rourke tweeted on Saturday.
Gerke said there were at least 21 civilian shooting victims. "We have to be more honest with ourselves".
US President Donald Trump said he had been briefed on the shooting and added that Federal Bureau of Investigation and other law enforcement agencies were "fully engaged".
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