Sandra Alvaro is the girlfriend of Columbian cartel hitman Javier Lariano Gaitan. She hid Gaitan after he shot Manuel and Natalie Ortega with an assault rifle in a crowded restaurant. She was arrested for harboring a fugitive when she and Gaitan were found.
Out of threats against her life, Sandra was eager to testify, but she was afraid to testify in an open court. She gave her account from prison to sell Gaitan out and get his conviction, which was a success. Gaitan was murdered by another hitman, Mr. Cristobal, to silence his testimony form the feds. Cristobal fled back to Columbia, and the cartel sent their contract killers and enforcers to execute and disappear the remaining witness.
Sandra's fate is left unknown. (SVU: "Prince of Darkness")