Reginald Hester, 51, gave a video confession admitting to starting the early morning blaze at the apartment block in Chicago , police said.
The Chicago Tribune reports that a woman living in the building had allegedly taken his $10 for sex and then refused to honour the deal. In anger, Hester is believed to have lit two fires, according to Cook County prosecutors.
Intense flames and heavy smoke trapped many residents in their apartments and prevented rescuers from reaching victims. Several people jumped from windows while others were freed by firefighters on ladders.
The fire claimed the lives of three young sisters and their neighbour. Baby Melanie Watson, aged three months, died from head injuries sustained when her father, Michael, jumped from a third-floor window with her in his arms.
The infant's sisters, four-year-old Madison Watson and Shaniya Staples, aged seven, were found dead in a hallway and living room of their third-floor apartment. Next-door neighbour, Kirk Johnson, 56, was also found dead in his home.
Judge Peggy Chiampas ordered Hester to be held without bond on four counts of first-degree murder and two counts of aggravated arson.
The woman at the centre of the sex accusations reportedly told police she Man started fire which killed three young sisters 'over failed sex deal' agree to perform a sex act for Hester but only did so in order to get the $10 he already owed her.
She raised the alarm after she spotted smoke near to where she had left him banging on the door to be let in.