Prosecutor John Jordan sets down a stiletto shoe entered into evidence during the trial against Ana Lilia Trujillo Tuesday, April 1, 2014, in Houston. Trujillo, 45, is charged with murder, accused of killing her 59-year-old boyfriend, Alf Stefan Andersson with the heel of a stiletto shoe, at his Museum District high-rise condominium in June 2013. (Brett Coomer/AP Photo/Houston Chronicle)

The weapon was a shoe — a size 9, navy blue, 5-inch stiletto heel pump.

And the question — in addition to guilty or not guilty — is whether this Houston murder case would have attracted so much attention had the weapon been a knife, a gun or even a hammer.

In any case, it all revolves around the shoe — used by a woman last June to kill her boyfriend, a professor at the University of Houston.

The shoe, prosecutors said Tuesday as they displayed it to a jury, was used to stab the man 25 times — 10 times to the head and 15 or more to the face, neck and arms.

The defendant, Ana Trujillo, 45, does not dispute that she used the shoe to kill her boyfriend, Alf Stefan Andersson, 59. But, she says, it was self-defense, not murder.

The couple had been out drinking at a bar in Houston and, police say, they started fighting after another man offered to buy Trujillo a drink. The fight continued afterward.

The cab driver who took them home, Rosemary Gomez, told jurors that Trujillo was belligerent and that Andersson was embarrassed by his girlfriend’s behavior.

The jury is now trying to piece together what happened after the couple got there.

Police say Trujillo called 911 the morning of June 9, 2013. When they arrived at the victim’s high-rise apartment, she answered the door covered in blood. Inside, police found Andersson lying in a hallway with Trujillo’s blue suede stiletto next to him, ABC News reported.

Prosecutor Sarah Mickelson, The Associated Press reported, said Trujillo, a native of Mexico, had a history of aggressive behavior in her on-again, off-again relationship with Andersson, a native of Sweden who taught at the university’s Center for Nuclear Receptor and Cell Signaling, specializing in women’s reproductive health.

Mickelson said:

“The one thing we can be sure of in this case is that Ana Trujillo is not a victim. … Ana Trujillo struck Stefan Andersson 25 times with the heel of her shoe while he lay on the floor and bled out.”

But Trujillo’s attorneys argue she was defending herself from Andersson with the only weapon she could get her hands on: that shoe.

Defense attorney John Carroll described Andersson as an alcoholic who became violent in those early morning hours when Trujillo told him she was going to leave him and go to a friend’s place. He told jurors that Andersson pinned Trujillo against a wall, grabbed her and threw her over a couch.

Carroll said:

“She couldn’t breathe. And she was begging and begging [Andersson] to let her go. … He started suffocating her. … She did the only thing she could do, take a weapon at her disposal, which was a shoe, and started hitting him.”

The trial will resume Wednesday and is expected to last at least one week. Trujillo is free on a $100,000 bond, the AP reported.