A cardiologist who once treated former President George H.W. Bush has been fatally shot, reports the Associated Press. Dr. Mark Hausknecht was heading north through Houston's Texas Medical Center at 9 a.m when another bicyclist pulled up beside him and fired two shots. He was hit at least once and was taken to a nearby hospital, where he later died.

Police have been trying to determine whether the shooting was a random or a targeted act. Hausknecht was 65 and previously treated the former president in February 2000 for an irregular heartbeat. He later appeared with Bush at a news conference after his treatment.

"Mark was a fantastic cardiologist and a good man," Bush said in a statement, offering his condolences to Hausknecht's family. "I will always be grateful for his exceptional, compassionate care." Houston Methodist Hospital's CEO Marc Boom said Hausknecht had been in medical practice for around 40 years, specializing in cardiovascular disease. 

“His patients appreciated his kind bedside manner and the extra time he took to answer their questions and fully explain their condition and treatment,” Marc Boom said in an email to fellow staff. “Our employees who worked with him said patients were so proud to call him their doctor.”