DALLAS—A Texas woman who said her 3-year-old son was killed in a road-rage shooting has been arrested on a child endangerment charge, police said Thursday. Lacravivonne Monique Washington, 26, kept a handgun in her sport utility vehicle where it was accessible to her children, ages 2-4, who were unrestrained, according to a Dallas police affidavit. The investigation began Monday when Washington brought her son Jalexus Washington to Medical City of Dallas hospital with a gunshot wound to the head. The child died, and the mother told police that he had been shot by an unknown person in a road-rage shooting. Investigators found no evidence of a road-rage shooting at the location the mother specified. But they did find a handgun in the glove compartment of Washington’s vehicle, which had no child restraints, the affidavit said. In a follow-up interview, Washington told police that her children were climbing back and forth …