A 28-year-old financial analyst said she was sexually assaulted by a driver claiming to work for Uber in late March. Now she wants to share her story to try to keep the same thing from happening to others. We are not naming her at her request.

The trouble started shortly after midnight on March 28th, when she was leaving the bar at the Standard High Line in Chelsea and all the yellow cabs outside were taken. She saw women go up to the window of a dark grey, late model sedan and ask if they could pay by credit card, then heard the driver say, "No, only cash."

"I thought, it's perfect: I have cash with me," she remembered.

The car had a laminated Uber sign in the passenger-side window. The woman was visiting from Europe for a yearlong stint at a major international bank and hadn't used the taxi app before, so she didn't know that Uber cars are ones you request and pay for on your phone. The driver told her to sit in front beside him, and she did.

"I didn't think much of it," she said.

She continued:

As soon as I got in he asked me for a cigarette and I gave it to him. And then he started saying to me how beautiful I am and stuff like that. And when we took off, he started touching me. First my leg. Ugh. He started touching me more and more in intimate places and my breasts and everything. And I tried to push him away all the time but of course you're not going to jump out of a driving car.

[...] He was constantly saying that he wanted to sleep with me and we should pull over so he could have some fun. Then he said to me, "Yeah, I'm married, so it's fine. I can do this stuff." Ugh. It was really really scary. The drive took about 15 or 20 minutes and when we stopped at the place I wanted to be he tried to kiss me and he actually did. Then he wanted to have $30 in cash and he said, "Yeah, you don't have to pay if you give me other services." So I just gave him the money and jumped out of the car.

From the street in Hell's Kitchen, she stared at the license plate as he drove away, trying to memorize the number. She wrote it down in her iPhone. Then she went inside to see the friends she had set out to meet, and told them everything that had just happened. She recalled:

I was shaking. Really, I am not a very emotional person. It's the feeling that you can't get out of something. You can't get out of the car and you can't stop them. My friends tried to calm me down and everything was fine then.

Two days passed before she went to the police.

"I thought I would be able to 'forget' about it, but my main reason for contacting the police is because I do not want any girl to ever have to experience what I did," she said. (She was also with her family that weekend, and said she wanted to make the call in private.)

The detective who interviewed her took the case very seriously, according to her account. Officers told her that the car was "probably not a real Uber car," and that the license plate number, which she is confident she wrote down accurately, does not match to any registered vehicle. In looking through a book of mugshots, she said she spotted a guy who she is "99 percent" sure was her attacker, but the investigator told her he had to have a sex crime on his record for officers to bring him in for an interview.

She hasn't heard from the police since, she said. She did not reach out to Uber regarding the attack, but a spokesman for the company said it has contacted the NYPD, and noted that Uber drivers shouldn't be picking up cash fares on the street.

"We are looking into this troubling report and have reached out to the NYPD to assist in any way we can," company rep Matthew Wing said. "Drivers accepting street hails is expressly prohibited in New York City."

The Police Department would say only that no arrest has been made in the case and that the investigation is ongoing.

The practice of cars for hire lining up with yellow cabs and soliciting rides is a longstanding—and illegal—practice, and one that should immediately set off alarm bells for passengers, according to a spokesman for the Taxi and Limousine Commission.

"If a vehicle is soliciting you to get in and it's not a yellow taxi—danger! Do not get into that vehicle," Allan Fromberg said, noting that even sanctioned livery cabs and black cars aren't allowed to pick up street hails. (Green cabs are also allowed to take street hails in the outer boroughs and above W. 110th and E. 96th streets in Manhattan.) "Even if it has a TLC license plate, that's a danger signal that it's not following the rules and regulations."

The Uber signs showing up in Manhattan taxi stands may be new, but Fromberg says misleading placards, unsanctioned street pickups, and un-licensed cars for hire keep taxi police busy all over the city. "There are an awful lot of permutations of how drivers will try to cleverly skirt the rules," he tells us.

And this is far from the first time a fake cabbie has sexually assaulted a fare. Two unlicensed livery cab drivers attacked four women in separate incidents in 2007 and 2008. Earlier this month, an actual Uber driver was suspended for trying to kiss a woman who fell asleep in his back seat.

As for the financier, there are a few details about the nightmarish ordeal that, however morbid, she is thankful for. For one, she had been visiting with friends at the Standard for about five hours before getting in the car that night, but fortunately she hadn't had much to drink.

"I think that he kind of hoped that I was drunk," she said, "because if I would have been, I wouldn't have been able to push him away."

And she is glad that she went to stop by her friend's place in Hell's Kitchen before heading home.

"[The attacker] doesn't know where I live, so I'm happy for that," she said.