EMBED >More News Videos Surveillance video shows a man near a flower cart hit Mary Rutkowski, knocking her to the ground outside the Buffalo Speedway store in early March.

HOUSTON, Texas (KTRK) -- A 51-year-old man who was convicted in the past for two assaults is the suspect in an attack of an elderly woman that was caught on camera outside of an H-E-B, authorities say.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.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.SEE ALSO: