Investigators arrested Erbie Bowser Wednesday night at the second crime scene, DeSoto police Cpt. Melissa Franks said. Charges are pending, Franks said.
Four people were also wounded in the attacks. Police released no information on Bowser's relationship with the victims, nor on the condition and identities of the survivors.
The first shooting took place at a house in southwest Dallas late Wednesday and the second happened about 15 minutes later in DeSoto, some 10 miles away, Dallas police Sgt. Warren Mitchell said.
Police were called around 10:30 p.m. to the home in southwest Dallas where they found four gunshot victims, two of whom had died, Mitchell said. The man then fled to DeSoto, where he is suspected of killing two people. Two boys, aged 11 and 13, survived that attack, DeSoto said.
A neighbor in DeSoto, Tommy Johnson, said he heard a loud boom Wednesday night coming from the direction of the home where the victims were later found.
"We thought it was coming from upstairs, because the kids are always upstairs making noise," Johnson said. "I went up and asked, 'Did y'all hear anything?' and one of my daughters said it came from outside. So I peeped out the front and that's when I saw a bunch of officers walking down the sidewalk and about 10 houses up."
Franks said she could not confirm that a grenade or other explosive device had been used in the DeSoto attack pending the results of an ATF and Dallas bomb squad investigation.
Neighbors wearing nightclothes came out of their homes before dawn Thursday to watch as police investigated the DeSoto crime scene.