Houston Police identified the man who they believe murdered Mark Hausknecht, the personal doctor of former President George H.W. Bush, last month.
Police Chief Art Acevedo said Wednesday that the department believes 62-year-old Joseph James Pappas was responsible for the June 20 death. Hausknecht, 65, was shot and killed while biking to work in Houston around 9 a.m. local time.
Hausknecht operated on Pappas' mother more than 20 years ago, but she died during surgery, which Acevedo said was the likely root of his actions.
"I don't know when he decided to do this, but I'm very familiar with how this murder was committed and there was a lot of planning that went into this," Acevedo said during a news conference.
Pappas, who has not been seen for at least 36 hours, is considered armed and dangerous, the police chief warned. He also said the suspect is likely still riding the 10-speed bicycle he was spotted with during the shooting.
Bush mourned the loss of his longtime physician at the time of his death.
"Mark was a fantastic cardiologist and a good man. I will always be grateful for his exceptional, compassionate care. His family is in our prayers," he said in a statement.
Acevedo said police believe that Pappas is suicidal.
