PC Jennifer Regan, 38, exchanged email addresses with the teenager, who has a history of mental health issues, after she helped talk her down from a bridge.
Ms Regan then emailed and texted the suicidal woman, who has a personality disorder, in a way that was “wholly inappropriate,” a misconduct panel found. She also invited the teenager to spend the night in her flat and allegedly made sexual advances.
Ms Regan who joined the force as a community support officer in 2009 before becoming a police officer in 2015, initiated the exchange by sending an email from her work address offering to meet “for a chat and a brew”.
She then sent the teenager her mobile number and exchanged a series of text messages during the first two weeks of July 2018, the misconduct panel heard.
"I'd like to keep in touch with you because I think you're a great person and I reckon you could make me smile a lot,” Ms Regan wrote. "The job introduced us, but it's you that made me want to say hi outside of that. I also think you're pretty amazing by the way,” she said. "All I'm saying is, I think you're a great person and I'm glad we met."
She added: "If you're feeling adventurous you could come and see me?"
Ms Regan offered to pay for a taxi for the woman to make the trip from Warrington to her flat in Manchester, and to drive her back home the following morning, it was said. At around 7pm, the teenager set off in the taxi to meet the police officer. But at 9.30pm, the teenager said she “felt uncomfortable and wanted to leave”.
The young woman left the flat, alleging the police officer had made sexual comments.
The following day, the officer texted the teen saying: "Hope I didn't upset you at all last night."
Ms Regan admitted sending the messages and inviting the woman to her flat, but denied she had made the sexual comments or acted inappropriately.
But the panel's findings said: "We found that the misconduct was very serious because it undermined the public’s trust in the police. We found that PC Regan still did not understand or appreciate the seriousness of what she had done, nor the importance of maintaining a clear distinction between professional and personal interests."
It added: "The misconduct was aggravated by the teenager's vulnerability. She is a fragile young woman, and the potential harm to her was great – she is unstable, and it takes very little to push her too far."
She has now been dismissed from her role with Cheshire Police without notice after a panel found her to be guilty of gross misconduct.