The individual may have been seeking revenge for his mother, who died during an operation performed by the doctor over 20 years ago, authorities have said.
Art Acevedo, Houston police chief, commented on the attack, stating: “There was a lot of planning that went into this. There was a lot of planning and, sadly, some skill.
“So, it appears that this may be a 20-year-old grudge that this man held.”
Mr Acevedo noted that Joseph James Pappas, the suspect in the investigation, should be regarded as armed, dangerous and possibly suicidal.
The attack took place on July 20, when Dr Mark Hausknecht was fatally shot while cycling to work at the Houston Methodist Hospital.
Reports indicate that the attacker rode past Mr Hausknecht before turning around and firing.
The police received a tip on Tuesday after CCTV video was released on Monday which showed the suspect, who someone claimed they recognised.
The investigators obtained a search warrant and entered Mr Pappas’ home at 4am on Wednesday, but no-one was present.
Mr Acevedo indicated there was evidence at the property linking Mr Pappas to the crime, but failed to elaborate on the nature of the evidence.
He added that the suspect appeared to own numerous guns.
Jim Herd, a neighbour of Mr Pappas, described the suspect as quiet, with few close friends.
He said: “He was a loner.”
Mr Pappas worked as a peace officer and reserve officer for Harris County Constable Precincts 2 and 7 from 1983 to 2013.
He was enrolled in law enforcement classes until August 2017.
Dr Hausknecht treated President Bush in 2000 for an irregular heartbeat after the former politician complained of lightheadedness.
More to follow…