The suspect in the fatal shooting of a prominent Houston doctor died by suicide, according to an official ruling by the Harris County Institute of Forensic Sciences.

Joseph James Pappas, 62, died Friday after shooting himself in the head during a confrontation with Houston police near Brays Bayou.

The former deputy constable and real estate agent was charged in the death of Dr. Mark Hausknecht, who was shot while biking to work in the Texas Medical Center on July 20.

Police said Pappas nursed a 20-year grudge against the doctor, who was operating on Pappas' mother when she died in 1997.

After days of no successful leads, police received a tip that Pappas was the suspect.

He was believed to be on the run for several days, until a Houston Parks Board worker spotted Pappas near a graffiti hotspot along Brays Bayou Friday and contacted police.

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An officer found Pappas several minutes later in the 8800 block of Bob White Drive. The former lawman was wearing body armor, refused to follow the officer's commands and mentioned suicide, police said.

A second police officer arrived, which is when Pappas took out a .22-caliber snub-nosed revolver and shot himself in the head, police said. He died in a yard, according to the medical examiner's report.