In his remarks, he distanced himself from Knox, a move his defense team has been pursuing in recent months as the pair prepare to appeal their murder conviction before Italy's Supreme Court next year.
Knox's version of the events the day her roommate, 21-year-old Meredith Kercher, was murdered is questionable, Sollecito said, calling it "imagination and hallucination."
But at the same news conference, Sollecito also maintained Knox's innocence, saying, "Amanda and I still believe she is innocent."
He continued, however, to distance himself from his ex-girlfriend. "I'm not saying that Amanda is responsible for all this situation, but they focus on her and they accuse her all the time, but I have nothing to do with all these circumstances and all these accusations."
"They are not Siamese twins -- one body with two heads," said Sollecito's attorney, Guilia Bongiorno.
In previous years, the two presented a united front. The new approach has been fueled by an appellate court's conviction in April and sentencing of Sollecito to 25 years in prison and Knox to 28 years.
In February, Sollecito told CNN, "There is nothing against me and nothing very strong against Amanda... And in my case, I really did nothing wrong, and I don't want to pay for someone else's peculiar behavior."
Knox and Sollecito were convicted 2008, but served only four years of 26-year sentences before their sentences were overturned. An appeals court reheard the case in 2011 and acquitted the pair after it was established DNA tests had been contaminated by police, but in 2013 the Supreme Court dismissed the acquittals, criticizing the lower court for "contradictions and inconsistencies" in its decision.
In April, an appeals court ruled that Kercher was killed in the apartment she and Knox shared in the town of Perugia, by multiple attackers, including Rudy Guede and Knox's boyfriend Rafaelle Sollecito, but it was Knox "who lashed the deadly wound to the throat" of Kercher.
The two will appeal their conviction before Italy's Supreme Court next year.