A Brooklyn sex offender, ​locked up on Rikers Island for beating his estranged girlfriend, took revenge on her less than 24 hours after being let out of jail — strangling the terrified woman in her own home, authorities said.

Jerome Rivers called Gia Pender on Thursday to ask if he could stay with her​. The call sent Pender, who had an order of protection against Rivers, scrambling to a neighbor. “Jerome is coming over​,​” ​she told the neighbor.

“​I​f anything happens to me, give this to my mother​,​”​ she added presciently.

Pender, 49, ​feared the 52-year-old​ Rivers​, who had been jailed for ​two months ​because he violated the terms of his release as a sex offender by attacking her. Rivers did time in 2013 on third-degree sex abuse charges, according to official records.

Rivers arrived at the woman’s Queens home, and then called cops around 6 a.m. the next day, saying he awoke to a “thump” and found Pender on the bedroom floor​, the Queens district attorney said.​

He later told cops he didn’t “have a reason to kill her,” according to the ​DA’s office, but​ he made a point of telling them she’d stolen his checks, “disrespected his mother, and had him locked up on trumped-up domestic abuse charges.”

Officials determined Pender had been strangled.

Rivers was arraigned Sunday on charges of second-degree murder and criminal contempt, and held without bail.

If convicted, he faces 25 years to life in prison.

Queens District Attorney Richard Brown called the killing “senseless,” adding​,​ “Domestic violence is a plague in our society and must end.”