Charging documents state Richard Derwin Howard has been behind bars since April 4 for an unrelated charge. Howard was identified as the suspect in the March 8 attack on Buffalo Speedway.
The assault was captured on surveillance video, showing Mary Rutkowski getting knocked to the ground outside the store.
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Rutkowski was seen leaving the H-E-B with her daughter when a man standing near a flower display hit her on the head.
Rutkowski's daughter, Annette Stewart, turned around to help as the suspect walked away pushing a wheelchair.
Last month, ABC13 Eyewitness News talked with Rutkowski.
"I want to know why," said Rutkowski. "Why he would pick me, of all people? I can't understand why anybody would hurt another person, especially an elderly person."
While a motive for the attack was not immediately known, documents state Howard had been convicted of aggravated assault with a deadly weapon in 1992, as well as assault of a family member impeding breath in 2011.
Crime Stoppers offered a reward of up to $5,000 for information leading to an arrest in the case.
For this case, Howard was charged with injury to an elderly individual, a third-degree felony.
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