Three people were killed Wednesday in a series of shootings in the Houston area, linked to a gunman who later died by suicide.

The first victim, a woman in Sugar Land, was found with multiple gunshot wounds in her SUV; she had been in a relationship with the shooter.

About 30 minutes later, the gunman shot a mechanic at an auto shop six miles away and then killed a witness filming nearby.

Authorities later found the shooter dead from a self-inflicted gunshot inside his vehicle, NBC News has reported.

Investigators are still working to determine the motive for the second and third killings.