Possibly linked to Ellen Burgess's disappearance
Made mysterious deals with DV Bordisso
Falsely accused Kevin of murder
Killed off many patients in experiments
Attacked Lucy in the park
Shot Mark Boardman
Kidnapped Kevin and Lucy
Poisoned Lucy with a drug that made her infertile
Knocked out Kevin and tried to drown herself and him
When Dr. Rachel Locke first came to town, she established herself a psychiatrist at General Hospital. Because Dr. Ellen Burgess knew her, Rachel arranged for Ellen to get a job in San Francisco, to get her out of the way. Ellen later mysteriously disappeared. Rachel took Ellen's old apartment as her own.
Rachel then became Julie Devlin's psychiatrist and defended her to all of the citizens of Port Charles, when Julie was on trial for being the General Homicide killer. Julie was the serial killer, but only because Greg Cooper had brainwashed her. Rachel crusaded to get Julie free.
We later found out Rachel had a connection to the devious D.V. Bordisso, shortly before he died of a gunshot wound.
Rachel and her mother Estelle hated Kevin Collins, because they believed he had killed Grace Reese when he was married to her. It went so far that Estelle poisoned the wedding cake at Kevin and Eve's wedding. Only Courtney ate some of the tainted cake, but she was okay.
After Scott and Lucy got full custody of Julie's daughter, Christina, Julie broke down. One afternoon, while Christina was visiting with Frank, her biological father, Julie knocked out Frank, and kidnapped Christina. Scott searched for them for a while, but it was no use. Lucy blamed Rachel for Julie kidnapping Christina.
Rachel's daughter, Livvie, came to town, and Rachel wasn't exactly thrilled. Livvie befriended Chris, and moved into Lucy's hotel room with her. Lucy told Kevin about Livvie, and he started having sessions with her secretly in the hotel room. When Chris found out about the sessions, he decided to use it against Rachel, and told her that Kevin was seeing a girl privately in a hotel room, but he didn't tell her it was Livvie. At that same time, Alison Barrington had killed a man named Cedric, but needed therapy. Kevin started out treating her, but Rachel stole her from him, to Alison's chagrin.
To get Kevin fired, Rachel told the hospital board about Kevin's secret hotel room visits with the girl. When Livvie found out about what her mother was doing, she was outraged. Livvie burst into the boardroom, and branded Rachel a liar. Meanwhile, Lucy started suspecting that Livvie might actually be Kevin's daughter. Eventually, Lucy did a DNA test and discovered the truth: Livvie really was Kevin's daughter. Chris found the test results and put them in Eve's (who was Kevin's wife at the time) locker. When Eve found them, she stormed into Kevin's office and demanded the truth, telling him that he was Livvie's father, unaware that Livvie was hiding in the room. Livvie came out of hiding and ran out of the office. Kevin confronted Rachel about it at Amanda Barrington's Phantom Ball, and Rachel lied that Kevin wasn't Livvie's father; his brother Ryan was. Rachel later told him that he really was Livvie's father after all. However, Kevin figured that Rachel couldn't really be Livvie's biological mother, and concluded that Grace, his dead ex-wife, was.
While all of this was going on, Ian and Eve were investigating how people were getting blue dots on their necks and dying because of it. They began to suspect that Dr. Mark Boardman was behind it. One afternoon, while she was in the park, Lucy was knocked unconscious, and she was taken to the hospital. A blue dot appeared on her neck. A couple of days later, Ian confronted Boardman in the GH parking garage, and Boardman held a gun on him. Suddenly, a car raced through the garage and Boardman was shot. He recovered, but was arrested for drug dealing.
Rachel confronted Kevin and drugged him. She also took Lucy and held the two of them captive in a lab. Rachel revealed that she was behind the blue dots and the people dying from them. It was because her mother Estelle had that condition that she was testing it on others in hopes of finding a cure. Also, she was the one that knocked Lucy out in the park. It was also revealed that Rachel was the one that shot Dr. Boardman. She then injected Lucy with a drug that would eventually cause her to become infertile. Ian and Eve burst into the lab and saved Kevin and Lucy, but Livvie came and helped Rachel escape, before anyone could catch her. Kevin later found Rachel on the docks, but she knocked the two of them into the water in an attempt to drown the both of them. Mac arrived just in time, but they were both unconscious. Kevin eventually regained consciousness, but Rachel did not. She was institutionalized for her crimes, and remained in a comatose state.
In the summer of 2001, vampire Caleb Morley created a vision of Rachel for Livvie, to get her to trust him. Livvie insisted to Jack and Alison that Rachel was out of the mental institution, but when she went to visit her, Rachel was still there, still in a coma.
Every once in a while, Livvie will visit Rachel, but she still hasn't come out of the coma.