HOUSTON – As more details come to light in the murder of a prominent Houston cardiologist, KPRC2 has learned that, on July 19, the day before Dr. Mark Hausknecht was gunned down, Joseph Pappas, the man who police believe is responsible for the crime, had a document notarized that essentially allowed him to transfer the deed to his property to a woman in Ohio.

Channel 2 Investigates learned that the woman on the receiving end of that General Warranty Deed is the mother of a woman Pappas helped decades ago.

A source told KPRC that the woman had drug problems, and Pappas, during his years as a deputy constable, helped the young woman get through a tough time.

Joe Donaldson owns the courier service that was hired to pick up the documents regarding the transaction and he said he saw Pappas that following Monday.

"It seemed strange. He was very nervous behind his barred gates, acting like he was looking around to make sure no one was out there," Donaldson, owner of Legal Express Texas, said.

Donaldson said that, when he later found out Pappas was a wanted man, he was speechless.

"I can't even put into words. I draw a blank now. I drew blank then. Just wow," Donaldson said.

Houston police believe Pappas is responsible for shooting and killing Hausknecht nearly two weeks ago in the Texas Medical Center.

TIMELINE of Dr. Hausknecht's killing

Investigators also believe an old grudge could be a motive in the case. Pappas' mother, who had been a patient of Hausknecht, died during surgery nearly 20 years ago.

"So shocking. Twenty years. That's unbelievable," Gloria Scherer, a neighbor of Pappas, said.

Days after the doctor was murdered, several items, including guns and ammunition, went up for sale on a popular firearms website believed to be connected to Pappas.

Listings appear to have been posted by the man accused of shooting a Houston doctor to death.

The phone number listed for the seller comes back to Pappas' real estate company.

These are just some of the many pieces to this complex murder case that police are left to sort through as they also search for Pappas.

"He is dangerous. He is capable and, if you spot him, please call 911," Houston Police Chief Art Acevedo said.