US teen, 18, BLINDFOLDED and handcuffed in custody after killing an undercover Italian cop with his friend - as neighbors from their wealthy San Francisco suburb reveal the pair were 'violent'

One of the American teenagers accused of murdering an undercover Italian police officer during a bungled drug deal was 'illegally blindfolded' before his interrogation. 

A photo of Gabriel Christian Natale-Hjorth, 18, shows him handcuffed, with his head bowed and a scarf covering his eyes. 

He spent a second night in a Rome jail Saturday with friend Finnegan Lee Elder, 19, after they were both interrogated for hours about their alleged roles in the murder of Vice Brigadier Mario Cerciello Rega.

Natale-Hjorth was said to have been blindfolded 'for a very few minutes, four or five' on Friday just before he was questioned about the fatal stabbing, Provincial Cmdr. Francesco Gargaro said.