The BBC said Knox, 21, testified in her trial in Perugia Friday that after allegedly being beaten by police, she wrongly implicated Patrick Lumumba in the death of her roommate, British exchange student Meredith Kercher.
"They (the officers questioning me) were suggesting Patrick Lumumba so the first thing I said was 'OK, Patrick,'" Knox alleged.
"The declarations were taken against my will," she added.
The BBC said police have denied any misconduct in the investigation into the November 2007 killing.
Knox is currently on trial with her 24-year-old Italian ex-boyfriend, Raffaele Sollecito. The two are accused of taking part in the sexual assault and death of Kercher.
A third person, Ivory Coast native Rudy Hermann Guede, was convicted of murder in October and sentenced to 30 years in prison.
Prosecutors allege physical evidence places Knox and Sollecito at the scene, and the defendants provided contradictory statements about their whereabouts the night Kercher died, CNN reported.