A "broken" Oscar Pistorius is described as his murder trial resumes in South Africa

PRETORIA, South Africa -- The Oscar Pistorius murder trial resumed Monday after a two-week recess, with the defense team calling its fourth witness in an attempt to bolster the double-amputee athlete's case that he killed his girlfriend by mistake last year.

The trial moved into its seventh week with testimony from Johan Stander, the first person Pistorius says he phoned after he shot Reeva Steenkamp at his home in the early hours of Feb. 14, 2013. Stander lived at the same gated community as Pistorius. Pistorius has said that Stander and his daughter were the first people to arrive on the scene after the shooting.

Stander's testimony follows a shaky start by Pistorius' defense, in which the Olympian's story of an accidental killing came under scrutiny as he was cross-examined by the chief prosecutor. Two defense experts also had their evidence undermined by prosecutor Gerrie Nel at the start of the defense's case.

Pistorius is charged with premeditated murder for shooting Steenkamp through a toilet stall door in his bathroom before dawn on Valentine's Day last year. He claims he mistook his girlfriend for a dangerous intruder. The prosecution charges he killed her intentionally after an argument.

The 27-year-old Pistorius, a multiple Paralympic champion and the first amputee to run at the Olympics, faces 25 years to life in prison if convicted on the premeditated murder charge.

Stander testified Monday that he had known Pistorius since 2009 after moving into the same gated community in the South African capital, Pretoria.

He said he received a panicked phone call from the world-famous runner at around 3:18 a.m. on the night of the fatal shooting.

"He (Pistorius) said on the call, 'Johan, please, please, please come to my house. Please. I shot Reeva,"' Stander testified. Stander said Pistorius told him on the call: "I thought she was in an intruder. Please come quick."

Stander then described what he said was Pistorius' "broken" state after he arrived at the runner's house to find him carrying his girlfriend downstairs.

"It's not something I would like to experience again, my lady," Stander said, addressing the judge who will deliver a verdict in the trial. "Because that young man walking down the stairs with the lady, with a young woman. His face. The expression of pain, the expression of sorrow. And he's crying."

Stander said Pistorius was "torn apart, broken, desperate."

The Reuters news agency says, "Stander also testified about previous break-ins at the estate but was forced to admit under cross-examination that it was 'generally a safe place"'.