FORT DODGE, Iowa — Tyrone Washington Jr. testified Friday that he acted in self-defense when he stabbed his ex-girlfriend, Justina Smith, on Aug. 5, 2013, at Swensrud Park in Northwood.

Smith died a short time later from her injuries.

“I told her I was done playing childish games, and I wanted to call it quits,” Washington said.

“When that happened she got upset and charged at me with a knife that came from her pocket.

“I was in fear for my life, so I defended myself. I tried to get the knife from her hand,” he said. “I used the knife in my own defense. I didn’t know if she had another weapon. I couldn’t believe it was happening.”

He fled the scene because of fear, Washington said.

“I’m in shock from the whole situation,” he said. “I jumped in the car and decided to leave. I felt the police weren’t going to believe me.”

Iowa Assistant Attorney General Laura Roan grilled Washington in cross-examination.

“You left her there,” Roan said of Washington fleeing the scene. “Is that what you do in self-defense? You run?���

Washington couldn’t remember how many times he had stabbed her.

Smith suffered two possibly fatal stab wounds to her liver and heart, medical examiner Jonathan Thompson said.

He said Smith also sustained 10 incise wounds to her upper body and upper thigh. Incise wounds are longer than they are deep.

Washington said he moved in with Smith in late May 2013. He said he didn’t feel welcome when he was introduced to Smith’s parents.

Forensic investigator Scott Stocksleger of the Iowa Department of Criminal Investigation testified Friday that blue jeans and a shirt belonging to Washington tested positive for blood matching the DNA of Smith. A knife that tested positive for the presence of blood also matched the profile of Smith. The odds that the blood belonged to someone other than Smith were less than one in 100 billion, Stocksleger said.

Washington led authorities on a high-speed chase the afternoon of Aug. 5, 2013, Lt. Neil Wellner of the Iowa State Patrol said.

Wellner said he had received notice around 3 p.m. Aug. 5, 2013, of a Pontiac Grand Prix that belonged to Smith, the day she died. The car was traveling eastbound toward the Illinois border, Wellner said.

Wellner said the Grand Prix sped up when the emergency lights turned on and speeds became in excess of 100 to 110 mph.

Washington had gotten to within 20 miles of the Illinois border in Scott County, Iowa, Wellner said.

The Grand Prix entered the ditch, Wellner said, and authorities tried to stop the car. Washington ended up speeding out of the ditch. The Grand Prix continued eastbound before swerving off the road and into a cornfield, heading south to southeast, Wellner said.

A short time later, the car was stopped and Washington was arrested. The video of the chase played Friday morning to the jury.

The trial will continue at 10 a.m. Monday at the Webster County Courthouse in Fort Dodge.