The suspect in the murder of a prominent cardiologist who treated former U.S. President George H.W. Bush killed himself in Houston Friday morning, police said.

According to Houston Police Chief Art Acevedo, a Houston Parks Board employee saw the suspect, 62-year-old Joseph James Pappas, in southwest Houston Friday morning. When approached, Pappas put his arms out and walked away.

Acevedo said when an officer arrived, Pappas had body armor on and a gun in his hand. He didn't comply with the officer's demands. As a second officer arrived, Pappas killed himself with a single shot in the head.

The police chief added that in a search of Pappas' home this week, investigators found an extensive intelligence file on Dr. Mark Hausknecht, who was gunned down on July 20 while riding his bike to work during the morning rush hour in the Texas Medical Center in Houston.

Earlier investigation showed that Pappas' mother died more than 20 years ago while in the care of Dr. Mark Hausknecht. Police believe that is the motive in the murder of the doctor.

Some reports said that Pappas was a former law enforcement officer and a highly skilled shooter who recently tried to sell several guns online.

In 2000, Hausknecht appeared at a news conference with George H.W. Bush after the former president was treated for an irregular heartbeat.