Lima, Peru (CNN) -- Joran van der Sloot said he elbowed murder victim Stephany Flores Ramirez in the face before strangling her and then suffocating her with his own shirt, according to transcripts of his confession.

The transcripts -- provided to CNN by an anonymous police source -- give shocking details of the murder van der Sloot is accused of and also give the public its first glimpse of why van der Sloot says the alleged murder took place. The source has not been named because he was not authorized to pass along the material.

"There was blood everywhere," van der Sloot said in the transcripts. "What am I going to do now. I had blood on my shirt. There was also blood on the bed, so, I took my shirt and put it on her face, pressing hard, until I killed Stephany."

Meanwhile, van der Sloot's Peruvian attorney resigned from the case, according to reports Monday from Peru's Foreign Press Association. Earlier, Maximo Altez Navarro told CNN that he didn't want to be van der Sloot's attorney anymore.

Peruvian authorities charged van der Sloot with murder last week in the death of Flores, a 21-year-old student. Van der Sloot, a 22-year-old Dutch citizen, has also been considered the main suspect in the well-publicized 2005 disappearance of Alabama teen Natalee Holloway in Aruba.

In the transcript, van der Sloot said that after Flores read the e-mail, she punched him in the face.

"At that moment impulsively, with my right elbow I hit her in the face exactly on top of the nose," van der Sloot said. "I think she started to faint. It affected me so that I grabbed her from the neck and strangled her for a minute."

Van der Sloot said he had a quick thought that he might try to hide the body but instead fled.

He was arrested in Chile on June 3 and was returned the next day to Peru. Along with killing Flores, who had a broken neck, he took money and bank cards from her wallet, police said.

Van der Sloot told police in Chile a different story of how Flores died when he was arrested there, according to transcripts. He blamed the death on robbers who had waited for him at his hotel in Peru.

"There was a man coming from the access door with a knife in his hand," van der Sloot said. "The man with the knife hit her in the face, making her bleed through the nose."

But Peru authorities said they had overwhelming evidence pointing to van der Sloot, and when he was transferred to Peru, van der Sloot confessed to the crime, police said.

Van der Sloot said he was in Peru for a poker tournament and had met Flores while he was gambling.

Police have said they think van der Sloot killed Flores to steal money she won from gambling.

Van der Sloot offered a different motive.

"After I responded with hitting her, I feared that she would go to the police and they would detain me for what was an impulsive act," van der Sloot said. "I think I wanted to kill her because I wasn't thinking."

Before he resigned from the case, Van der Sloot's lawyer said he planned to ask the judge to strike down van der Sloot's confession because he was not properly represented when he was interrogated.

Peruvian police have defended the interrogation and said van der Sloot's confession was acquired legally.