Hausknecht once treated former President George H.W. Bush. He was riding his bike to work when another cyclist fatally shot him and fled the scene, police said.
Houston Methodist remembered him in a statement:
His patients appreciated his kind bedside manner and the extra time he took to answer their questions. ... Our employees who worked with him said patients were so proud to call him their doctor.
Not only was he revered by his patients but Mark was highly regarded among his peers and colleagues. ... We wish Mark's family and friends peace and prayers as they cope with their loss.
Former President George H.W. Bush offered his condolences in a statement: "Mark was a fantastic cardiologist and a good man," Bush said. "I will always be grateful for his exceptional, compassionate care. His family is in our prayers."
The shooting suspect was described as a white or Hispanic man wearing a dark jacket.
The Houston Police Department is currently searching the area for the suspect. An HPD homicide unit is investigating the scene.