Newly released surveillance images show the moments before ex-President George H.W. Bush’s former doctor was shot and killed by another man while riding a bicycle to work.

Dr. Mark Hausknecht, 65, can be seen in three of the surveillance images, provided by the Houston police department, riding north on Main Street with the suspect also riding a bicycle behind the doctor on Friday morning.

The fourth image shows the suspect heading west on a different street after the shooting took place just blocks away.

A surveillance photo shows Dr. Hausknecht, in green, and the suspect, in red. The shooting happened moments later, one block away. Houston Police

“Our family would like to thank law enforcement, the medical community, and so many colleagues, patients, friends and neighbors who have reached out to support us during this difficult time, Hausknecht’s wife Georgia said in a statement.

“Mark loved this city. To honor him — work hard, be responsible, patient, tolerant and compassionate.”

Houston police have released a sketch of the suspect.

Houston Police released a composite sketch of the suspect wanted in the killing of Dr. Mark Hausknecht. Houston Police

The shooting occurred around 9 a.m. local time when the suspect rode past Hausknecht, turned and fired two shots, according to Houston police assistant chief Troy Finner.

When authorities arrived at the scene, Hausknecht was already taken to Ben Taub Hospital, a local trauma center, and pronounced dead shortly thereafter, according to Finner.

“Mark was a fantastic cardiologist and a good man, President Bush said. “I will always be grateful for his exceptional, compassionate care. His family is in our prayers.”

Hausknecht worked as a cardiologist at the Houston Methodist Hospital and the DeBakey Heart & Vascular Center, according to a public relations person for Houston Methodist.

Authorities still do not know whether Hausknecht was intentionally targeted by the suspect or a random attack, according to Finner.

A witness described the suspect as a white or Hispanic male, 5 feet 10 inches tall with a slender build and around 30-years-old. He was reportedly wearing a baseball hat, sunglasses, a grey warm-up jacket and khaki shorts, according to police.