Miranda Roman  (formerly Miranda Martins) was Lorelei Martins' sister and Dana Martins' daughter. When she was two years old, Dana, who had a drug addiction, could not afford to keep both children. Seeing as Miranda was younger and less attached, Dana contacted a rich Romanian couple who could provide Miranda with love, care and opportunities to grow. In exchange for giving Miranda to them, they provided money to Dana and the now torn Lorelei. Both Dana and Lorelei suffered for this choice (Dana states that she lost two daughters that day). Years later, when Miranda was in high school, she became depressed and was put in touch with a counselor and a lot of memories resurfaced. She was reunited with Lorelei and they became extremely close, retreating on occasion to a cabin Miranda owned.
She was abducted, with the help of Julia Howard, by Jason Lennon, a serial killer and serial rapist friend of Red John, and took to him. Miranda is raped (maybe by Red John himself), and left to die in an abandoned warehouse and it is Red John who was responsible. Chained and suffering from a heat stroke, she managed to carve "Roy" in the floor, or in other words Roy Tagliaferro (an alias that Red John used when courting sexual partners, such as Rosalind Harker). It is assumed that he did this to lure Lorelei into his inner circle, and that could not be completed while the two were so compact.
In present, Patrick Jane is given a picture of the scene at Miranda's murder by fax. (The CBI presuming he has been abducted.) He gives it to Lorelei and they visit the cabin where she used to visit with Miranda. He asks her to figure out for herself whether Red John killed her sister and to contact him when she found out.
Lorelei avenges Miranda's death, torturing and killing Julia and injuring Lennon, to understand that Red John is really the killer of her sister. Lorelei wanted to kill Red John, but he murders her.
Miranda was photographed, mentioned and was one of the key figures in Season 5 episode 8 Red Sails In The Sunset.