Drivers license photo of accused murderer Terrance Deering Black. (credit: TxDOT)

MCKINNEY (CBSDFW.COM/AP) — The mother of a North Texas fitness instructor found dead in a field last year testified Monday during the first day of the trial of Terrance Deering Black, who is charged with capital murder in the 2011 death of Susan Loper.

Loper’s mother, Catherine Miller, told the court her daughter’s the victim’s ex-boyfriend seemed obsessed with her daughter, giving her expensive gifts, such as a 40-inch TV and a laptop.

“It was almost like an obsession with Susan,” Miller testified.

Loper, a 40-year-old Pilates instructor, was found beaten to death on April 20, 2011. The body of the single mother was found in a field in Frisco – just off the Dallas North Tollway. Loper’s SUV was found in the same area and was located by tracking her TollTag.

Black was arrested in Arizona after he jumped and fell 25 feet into part of the Grand Canyon two days after Loper’s body was found. Investigators found two suicide notes from Black, but his defense attorney insisted that a suicide attempt was not proof that Black killed Loper.

In opening statements, prosecutors said the now 50-year-old Black had a fixation on Loper that lasted after their relationship ended in 2009. Prosecuting attorney John Schomburger said Black was waiting for Loper when she arrived at work on April 19, 2011. Black tried to shoot her, but the gun wasn’t working, Schomburger argued.

When police arrived at the Pilates studio at Gleneagles Country Club, they found three bullets, blood and signs of a struggle, Schomburger said.

Schomburger also said Black’s DNA was found in Loper’s car, which Schomburger argued Black used to transport her beaten body to the field.

The defense argued that police should have spent more time investigating other suspects, including the victim’s most recent boyfriend.

Defense attorney Jim Burnham said Loper had broken up with Jayson Hayes a few weeks before her death, and his fingerprints were found at the crime scene. Burnham added that Hayes was the one who pointed toward Black as Loper’s killer.

“This is a case, ladies and gentlemen, of a rush to judgment,” Burnham told jurors.

Another witness, Lisa Bacic, testified that when she arrived at the country club for a Pilates class, the studio was in disarray. A ripped privacy screen and a plant had been tipped over, and she saw broken glass and a bullet on the floor.

“Susan was very particular,” Bacic testified. “She would keep her studio pristine.”

Black faces an automatic life sentence without parole if convicted.

The trial is expected to continue for two weeks.

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