(CNN) -- A Texas man went on a gun attack in two cities late Wednesday, killing four people, including two at his ex-girlfriend's home, police said. He wounded four more.
When he saw that his ex-girlfriend was not at her Dallas home, he stopped shooting there and quickly drove to a second home in the city of DeSoto, where he found her, CNN affiliate WFAA reported.
There, he used "some sort of explosive device," then opened fire on the people inside, DeSoto police spokeswoman Melissa Franks said.
Police arrested suspect Erbie Bowser when he ran out of ammunition, she said.
Charges are pending. Dallas and DeSoto investigators are working together on the case. The U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives is investigating the nature of the explosive device, Franks said.
Police said Bowser moved quickly from the first shooting to the second one.
The first emergency call reached Dallas police at 10:30 p.m. Wednesday. When they responded, they found two victims dead, police said. Two more people were wounded but still alive.
At 10:45 p.m., a 911 call came in from the DeSoto home as gunshots were fired, Franks said.
There, two adults were fatally shot, and two boys, ages 11 and 13, were wounded by gunfire, Franks said. She would not say whether the ex-girlfriend was shot.
Police said they arrived quickly and arrested Bowser at the home.
Information on the boys' conditions wasn't available.
CNN's Paul Caron, Marlena Baldacci and Tina Burnside reported from Atlanta; Ben Brumfield reported and wrote from Atlanta.