HOUSTON – Joseph Pappas, the man accused of killing Dr. Mark Hausknecht, killed himself Friday in a southwest Houston neighborhood as officers surrounded him, police said.

Houston police Chief Art Acevedo said a city employee was patrolling the Brays Bayou Greenway Trail when he spotted a person about 9:20 a.m. in an area known to have a graffiti problem. He said the employee approached the man who began walking away. He said the employee found a wallet left behind by the man, which identified him as Pappas.

Police said the employee followed Pappas and called police several times to give updates on Pappas' location. An officer moved in on Pappas near the intersection of Bob White Drive and Imogene Street, and he refused to show his hands to the officer, police said. Pappas only raised his left hand, according to Acevedo. Investigators said Pappas had a snubnosed revolver hiding in his right hand. When Pappas hid behind a tree in the front yard of a residence, an officer heard Pappas say, "suicide" as he placed a handgun to his head, according to investigators. The officer heard a gunshot and saw Pappas collapse, police said.

"After I heard the gunshot, I saw the hand go down," a witness said.

Acevedo said Pappas was wearing a bulletproof vest when he killed himself. According to investigators, he also had at least two additional firearms and ammunition.

"Police had indicated that the man had evidently shot himself, that the police evidently were coming up to him and asking him to put his hands up, and he put one arm up and, this is according to what this man said the police said, and evidently the man pulled out his gun and shot himself," said a person who lives in the neighborhood.

Neighbor said police said there was a suspect who shot himself in front of her neighbor's home @KPRC2 pic.twitter.com/SYvRpDptz6 — KPRC2 Rose-Ann Aragon (@KPRC2RoseAnn) August 3, 2018

Neighbor said they heard commotion. HPD Chase's suspect in southwest Houston https://www.click2houston.com/news/joseph-pappas-suspect-in-slaying-of-doctor-found-dead-in-southwest-houston Posted by KPRC2 Rose-Ann Aragon on Friday, August 3, 2018

No officers were injured in the incident.

The scene where Pappas committed suicide is about 3.5 miles from his Westbury home.

Acevedo said he is convinced that if the officers had not cornered Pappas a shootout would have occurred.

VIDEO: Acevedo discusses Pappas' suicide | ver en Español

The chief said that investigators are still trying to piece together Pappas' movements since the doctor's shooting.

He said an extensive file on Hausknecht was found inside Pappas' home when investigators searched it earlier this week. That file contained information on Hausknecht's cars, where he lived, his place of employment and more.

A sheet of paper within the file contained names of more than a dozen employees of the Texas Medical Center.

"We haven't been able to definitively say that was a hit list or not," Acevedo said.

PHOTOS: Scene where Pappas was found dead

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Acevedo said police have yet to find the bicycle Pappas was riding on the day of the shooting.

Hausknecht's wife, Dr. Georgia Hsieh released the following statement:

"I echo the sentiments of Houston Police Department Chief Acevedo this morning in thanking the numerous departments, communities, and individuals involved whose teamwork and cooperation lead to the rapid resolution of this case.

"Media’s role in keeping the public informed is also acknowledged. The family can never adequately thank our friends and neighbors who have loved and supported us. I am most grateful, however, for the many wonderful years, our family shared together."

Mayor Sylvester Turner released a statement Friday afternoon that read:

"The potential threat to the City from an accused murderer considered armed and dangerous is now over, closing another chapter of this horrific tragedy. And once again it involved heroic acts by frontline officers of the Houston Police Department, which has my gratitude for how it has handled this case and so many others.

"But they could not have succeeded in this case without information and support from members of the public. I encourage everyone who has information about pending and future cases to come forward and help our city save lives."

Neighbors react to Pappas' death

Some neighbors said they saw Pappas riding his bicycle back and forth on the Robindell neighborhood streets. Others saw him near a pedestrian bridge near Brays Bayou. However, he was ultimately last seen outside a woman's home on Bob White Drive near Imogene Street, where police say he took his life.

"We all came out of our house, and we were just shocked," Laurel Parks said.

Parks heard commotion outside her window on Bob White Drive.

"Walked across the street to my neighbor. She said, 'There is a body,'" Parks said.

Pappas' body was lying just outside her neighbor's home on Imogene Street.

Don Burruto's neighbor said he'd seen Pappas near the bayou.

"Saw him camping under the bridge right there behind the water tower -- which is very much off the beaten path -- there's no real road over it -- and I guess if I was looking to hide, that would be a good place to," Burruto said.

Others also said they'd seen him in the neighborhood.

"I've seen him in the neighborhood just passing by," Corey Byrd said.

"[A police officer] pulled his weapon, and had it drawn on whoever was behind the tree with his hand up," said another witness, who didn't want to be identified. Police said Pappas had been told to raise both hands.

For the Robindell neighbors, they are relieved the manhunt is over.

"It's sad, but it's probably a better ending than it could've been," Mary McMann said. "I'm just so proud of the police for the way they handled it. They did they best they could to try to bring them in. Everyone did their job."

The witness who gave police the tip was a member of the Houston Parks Board, a private organization. The board sent out a statement saying they are proud of him for his cooperation with police:

“The Houston Police Department (HPD) has worked hard to investigate the shocking murder of Dr. Mark Hausknecht. We are thankful that the investigation has come to an end.

"Today, a Houston Parks Board employee was doing his job on Brays Bayou Greenway when he was able to provide valuable information to the police department. We are proud of him and his swift action. Since he is a witness to an investigation, HPD has advised he not participate in press interviews, and our colleague agrees. Houston Parks Board supports this decision and we thank you for respecting the privacy of our colleague.

"I’d like to echo Mayor Turner and Chief Acevedo and thank the news media and fellow citizens for their help with this investigation. This is a great example of how we all came together for the safety of our city.”

Timeline of the case

Hausknecht was shot three times July 20 while biking through the Texas Medical Center. Investigators said another cyclist shot him three times.

Over the course of nearly two weeks, police released several images and videos taken from surveillance cameras. They showed Hausknecht being followed by another cyclist and showed that cyclist fleeing the scene after the shooting.

One of those videos led to the identification of Pappas as the suspect, according to Acevedo.

Acevedo said it appears Pappas held a grudge against Hausknecht after his mother died on the doctor’s operating table 20 years ago.

Explore an interactive timeline of the case below:

Want to see a larger version of this timeline? Click or tap here.