Investigators in Peru are leaning on van der Sloot to give them information about Holloway's 2005 disappearance.
Master hackers hired by Peruvian authorities to examine his laptop have reportedly found pictures and other information relating to Holloway.
Police investigators told Lima's La Republica newspaper that van der Sloot's bombshell confession came late Monday night when he tearfully admitted that he grabbed Flores by the neck when she began reading articles about him on the Internet.
"I did not want to do it. The girl intruded into my private life," he told investigators, according to La Republica. "She had no right."
"I confronted her," he continued. "She was frightened, we argued and she wanted to get away. I grabbed her by the neck and I hit her."
Flores' battered body was found three days later, her neck broken. van der Sloot, who had crossed the border into Chile, was nabbed there and extradited back to Peru.