Martha Perez, 52, killed by hit-and-run driver at Alpha and Preston Roads in northern Dallas, Texas

Detectives aren’t sure what kind of car it was — something white, they say, possibly a Mercury Grand Marquis or “a Ford Crown Victoria with 20-inch rims.” And the dark-tinted windows made it difficult to see the driver, which is why, for now, there is no description provided of the person behind the wheel.

But there are a few clues, among them: “The right rear tire has a (donut) spare tire on it,” says a release from the Dallas Police Department.” Gutierrez says the suspect’s vehicle should also have some damage on the left side, to the grill and the front quarter panel.