A Brooklyn convict plotted with a fellow Rikers Island inmate to murder a key witness who saw him fleeing from a terrifying home invasion – saying “I don’t care how you do it, I just want him dead,” prosecutors said Thursday.

Joseph Lombardo, 55, was convicted Wednesday of bursting into a Gravesend home – armed and wearing a mask – and demanding money from the women and 11-year-old girl inside in 2012.

But beginning in May the ex-con began asking an inmate to “take care of a witness,” the Brooklyn District Attorney said in a press release Thursday.

“The defendant used another inmate to try to hire a hitman,” assistant district attorney Sarah Nadeau said in court Thursday.

The inmate ratted Lombardo out to Corrections investigators, who told the Brooklyn DA’s office.

The DA’s office sent an undercover investigator who posed as a hitman to meet with Lombardo – and that’s when the ex-con really opened up about his plan to kill the man who saw him running away from the home invasion, the DA’s office said.

“The defendant allegedly proceeded to draw a map of the deli with instructions on how to access the apartment. He also allegedly suggested the undercover steal cash and cigarettes to stage the hit as a robbery gone bad,” according to the DA press release – which also said Lombardo offered the hitman $10,000 to rub out the witness.

Lombardo faces 25 years to life in prison when he is sentenced on the home invasion October 17.

He also faces 25 years to life behind bars if convicted of conspiracy and solicitation to commit murder.

He pleaded not guilty at his arraignment Thursday.