Danny Jones was a drug dealer who appeared to have had Lennie Briscoe's daughter Cathy steal drugs for him. Eventually, he murdered her.
When Cathy is arrested, she turns on Danny and helps set up a sting operation to catch him. He later appears in court and witnesses Cathy testify against him. His defense attorney portrays Cathy as corrupt like her father. After her testimony, the jury remains deadlocked on their decision and the judge is forced to declare a mistrial while bail is continued. Danny makes bail and later shoots Cathy twice in the head in retaliation. (L&O: "Damaged")
Danny is later seen leaning against a building with his associates as Briscoe and his partner Rey Curtis observe him. Danny smiles at Briscoe and they leave after they get a lead in the case they are working. One of Briscoe's informants offers to kill Jones in exchange for Briscoe disposing of incriminating evidence; it is left ambiguous whether Briscoe went through with the deal. (L&O: "Monster")