Authorities believe Joseph James Pappas' motive for gunning down Dr. Mark Hausknecht was over a 20-year-old grudge involving Pappas' mother.
"Great guy, nice, friendly with everyone. Never heard a negative, or ugly word out of his mouth," said Marc Johnson, a firearms instructor who met Pappas decades ago at a local shooting range. Over the years, they would meet up at various ranges and shoot, then grab dinner.
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On Wednesday, Pappas was charged for the July 20 murder of Dr. Hausknecht as he rode his bicycle to work in the Texas Medical Center.
The 62-year-old suspect was in law enforcement for 30 years, including being a peace officer for two different constables' offices, and most recently serving as a reserve officer.
Johnson describes Pappas as an excellent marksman. "Very skilled. Very skilled."
WATCH: HPD announces charges against Joseph Pappas
For residents of Westbury, the tight-knit community where Pappas grew up, he was known as a just a quiet neighbor.
"He was a good neighbor, a good son, and grew up in the neighborhood, lived in the neighborhood, and waved as you went by, just a regular guy," said Civic Club President Becky Edmondson, who served on the board with Pappas' father years ago.
That outward appearance of normalcy is what makes the accusation that Pappas killed Dr. Hausknecht even more shocking. County records show Pappas recently deeded over his Westbury home to a woman in Ohio.
Johnson also remarked that Pappas seemed different when the two ran into each other at a westside shopping center a few months ago.
"He seemed depressed when I saw him. Just not the happy, go-lucky Joe that I know. Which kind of it, it was noticeable."
Anyone with information on Pappas' whereabouts is urged to contact the Houston Police Department Homicide Unit at 713-308-3600 or Crime Stoppers at 713-222-TIPS.
Pappas is considered armed and dangerous, and police believe he may be suicidal.
SEE ALSO: Mark Hausknecht seen in new surveillance photos with suspect who shot and killed him
On Thursday, Dr. Hausknecht's family released the following statement pleading for the public's help to find Pappas:
The Hausknecht family is very grateful for the diligent hard work and professionalism of the Houston Police Department and all the other agencies, organizations and countless individuals who have contributed to the identification of Joseph James Pappas as the suspect in the murder of Dr. Mark Hausknecht.
The family further urges the public to focus on the photo of the suspect and other information about the suspect released by HPD Chief Acevedo yesterday. They ask for the public's continued support of law enforcement's efforts in finding and apprehending this dangerous and armed individual as soon as possible.
The family urges that if you know anything about the possible whereabouts of the suspect, please contact Houston Police Department as soon as possible.
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