(CNN) -- Joran van der Sloot goes on trial Friday in Peru, ready to admit to killing a 21-year-old woman while planning to fight more stringent charges that could land him more time in prison, his lawyer said.
About six and a half years ago, the Dutch national was considered the prime suspect in the case of Alabama teenager Natalee Holloway, who vanished while on a graduation trip to the Caribbean island of Aruba. He was arrested twice but never charged in connection with Holloway's disappearance, which is still unsolved.
Yet van der Sloot's trial in another high-profile case, which his lawyer said has a tenuous connection with the Holloway story, is set to go forward Friday.
The 24-year-old is accused of killing Stephany Flores in his Lima hotel room in May 2010. Police say that he took money and bank cards from her wallet and fled to Chile, where he was arrested a few days later.
Van der Sloot was charged last September with "qualified murder" and simple robbery, which together could carry a sentence of up to 30 years in prison. Flores' family later tried -- unsuccessfully -- to convince three judges from the superior court of Lima to impose an even more serious slate of charges that could have included a life sentence.
His attorney, Luis Jimenez Navarro, told InSession on Wednesday that his client "will accept at trial the charge of simple homicide. ... What he will not accept are the aggravated charges."
"We are sure that -- with support from ... experts -- it will be determined that Joran was living in a post-traumatic state during the attack," Navarro said, adding that "psychologists and psychiatrists" will testify at van der Sloot's upcoming trial.
He pointed to the Holloway case, noting that the fatal attack on Flores occurred exactly five years after the Alabama girl went missing. It has been widely reported that van der Sloot killed the woman after he believed she saw something on the Internet relating to Holloway.
"He is a young man ... who has practically lived persecuted for a crime he says he did not commit ... or for a disappearance that he cannot explain," the lawyer said of van der Sloot. "Movies and books have been made ... At that age, and with other characteristics of his psychological profile, ... in that moment, he felt threatened and reacted in a brutal manner."
Jimenez said that he and his client will ask the judges for a 7- to 20-year sentence, "which are the legal sentencing parameters for homicide." He contended his client never planned to "entrap ... the future victim in a casino where there are more than 30 cameras" while he was staying in a room registered under his legal name, and then kill her.
"There was no premeditation," the lawyer argued.
The victim's family, including her father Ricardo Flores, had pushed for stiffer charges and claimed that van der Sloot hasn't looked "remorseful" in court appearances.
"He had an indifferent and prideful attitude. He looks as if he has everything under control. He looks better than when he appeared on TV after he was arrested," Ricardo Flores told CNN last year.
Three judges will preside over Van der Sloot's trial, starting Friday, and there is no jury.
The proceedings will begin with the prosecutor stating the "facts" that have been proven in the case, as well as detailing the alleged crimes committed, according to Peruvian lawyer and University of Oklahoma professor Giovanna Gismondi. Then the lead judge will talk generally about the crime, after which van der Sloot's side will have the floor.
This round of the case could include testimony from the accused, though Navarro said that van der Sloot likely wouldn't give a statement Friday though he may answer questions from judges. The other scheduled trial dates are next Tuesday and Thursday, though the judges could adjust the plans at any time.
Besides the Flores' murder trial, van der Sloot also faces extradition charges to the United States. In June 2010, a federal grand jury in Alabama indicted him on charges of wire fraud and extortion after allegations surfaced that he tried to extort $250,000 from Holloway's mother. He was given a total of $25,000, and authorities believe he used that money to travel to Peru and participate in a poker tournament, where he met Flores.
InSession's Jean Casarez and Mayra Cuevas contributed to this report.