LANCASTER, Texas -- Police in the Dallas-area suburb of Lancaster have arrested a man believed to have shot and killed two people at a Dollar General store on San Antonio's northeast side Tuesday morning, San Antonio police said.

SWAT officers threw a flashbang device near the vehicle to distract the man, and threw tear gas inside the vehicle before pulling the man from the car. He was injured, but it was unclear if he shot himself, but he was taken to an unnamed hospital, according to Dallas County Constables. He was led away from the scene in handcuffs and under his own power.

Dallas County constables said the suspect, identified as 31-year-old Alonso Mendoza, was being pulled over for a traffic violation when constables noticed he held a gun to his head, according to a report from CBS11.com in Dallas. The standoff was still going as of 3:50 p.m.

A gunman opened fire inside the store Tuesday morning, killing a male and female employee, San Antonio Police Chief Bill McManus said.

The man died at the scene and the woman was airlifted to University Hospital, where she was pronounced dead.

The victims have been identified as 40-year-old Clarence Blades and 25-year-old Misty Dawn Espinoza. Police said Mendoza and Espinoza were recently married.

Mendoza allegedly entered through the front of the store in the 11400 block of Perrin Beitel around 9 a.m. and made his way to the back, where the victims were stocking shelves, McManus said.

A customer was in the store at the time of the shooting but was not harmed, McManus said.

Police were initially investigating the shooting as an armed robbery attempt, but a relative of one of the victims told KSAT 12 News that the motive may be related to an ongoing domestic situation involving the female victim.

The gunman left in a white car and McManus said it didn't appear anyone was in the vehicle waiting for him.

Melissa Buck, a manager of a Meineke muffler shop nearby, knew the female victim.

"She's a good friend of ours. All of them are very good friends of ours," Buck said. "We take care of each other in the neighborhood and something to happen this close to us makes us very, very uneasy."

Family Reacts

Family members of Espinoza said they were distraught over the shooting and called it a senseless crime of domestic violence.

"We're going to miss her very much," said sister Roxanne Espinoza. "She was the baby in the family. This is very hard as anyone can imagine."

Misty Espinoza had been married to Mendoza for only two weeks before she decided to part ways. Roxanne Espinoza said her sister split from Mendoza because he was obseesive and controlling.

"He snapped," Roxanne Espinoza said. "He believed she was cheating on him, which she wasn't. She was dedicated to her job, getting ready to become a district manager, and he just snapped."

Misty Espinoza is survived by two daughters.