Suspect in murder of Houston cardiologist kills himself as police close in

The days-long search for the suspected killer of a Houston doctor who once treated former President George H.W. Bush came to an abrupt end Friday morning when he took his own life as authorities closed in on him, police said.

Joseph James Pappas, 62, died from a self-inflicted gunshot wound after police officers located and confronted him in a residential neighborhood in southwest Houston, according to the city's police chief, Art Acevedo.

Pappas was pronounced dead on the scene.

"This is our suspect. The suspect is deceased," Acevedo announced at a press conference Friday. "He committed suicide when he was confronted by two members of the Houston Police Department here in the southwest division."

Pappas was wanted in the murder of local cardiologist Mark Hausknecht, who previously treated the 41st president.

Hausknecht, 65, was gunned down on July 20 while riding his bike to work at Houston Methodist Hospital, which is part of the Texas Medical Center.

"He was a brilliant physician, and he's touched a lot of lives," Acevedo said at a press conference Wednesday.

Houston police have been searching for Pappas for the past several days since identifying him as the murder suspect and issuing a warrant for his arrest.

Police conducted a search warrant at Pappas' residence Tuesday night into Wednesday morning and discovered a "very extensive intelligence file" that the suspect had allegedly gathered on Hausknecht, according to Acevedo.

The file also contained the names of "a couple dozen" potential doctors and other employees of the Texas Medical Center, which was notified of the discovery.

"He knew everything there was to know," Acevedo told reporters Friday.

Police believe Pappas may have had a longtime grudge against Hausknecht. Some 20 years ago, Pappas' mother died while the surgeon was operating on her, according to Acevedo.

On Friday morning, around 9:30 a.m. local time, police received a call about a confirmed sighting. The witness, who works for the Houston Parks Board, told police he was on duty when he came across an individual sitting near Sims Bayou whom he thought might be a graffiti vandal.

The witness said he made contact with the man, who stretched his arms out and walked away.

The witness told police he then found a wallet near where the man had been sitting, and inside was an identification card for Pappas.

Within minutes, police units were deployed to the area and an officer spotted Pappas, according to Acevedo. The officer got out of his marked police vehicle, drew his gun at Pappas and repeatedly ordered him to put his hands in the air.

Pappas, who was wearing a bullet-proof vest, wasn't complying and kept his right hand concealed. He apparently mentioned "something about suicide" to the officer, Acevedo said.

Another officer arrived on scene to assist. As the two officers began positioning themselves in a "T formation" on the suspect, Pappas took out a gun and shot himself in the head, Acevedo said.

"I'm thankful that we're going to end this week with a great sense of relief in the city of Houston and the Texas Medical Center," the police chief said. "I'm convinced that had we not had that second officer arrive from a different angle, we might have had a shootout here."

ABC News' Jennifer Harrison, Julia Jacobo, Marcus Moore and Gina Sunseri contributed to this report.