After you've hacked terminals and discovered the vulnerable pieces of information leaking out against Liara in Mass Effect 2 Legendary Edition, you can speak to her later to ask how you can help further. The next step is to figure out the Observer's identity, someone who has been working with the Shadow Broker and reporting back to them about Liara. The trick to discovering the correct information is that you need to find all of the hackable data points on Illium and then report back to Liara at the correct time. Who is the Observer? Find more data - Datapoint locations Once you've spoken to Liara and you have the quest, the next step is to visit each of the data point locations on Illium and receive the information they have on them. It's important to note that while these terminals provide information about the Observer's identity, you're better off ignoring it and instead focus on visiting each location. There are five locations in total. Screenshot by Gamepur After you've collected each of the data points, access any of them, and then choose the 'Call Liara' option. Shepard will speak with Liara, and you'll have a wheel of options available to you. The choice you want to pick will be 'None of the suspects fit,' and then proceed. Shepard details how the person in these messages is female, and all of the suspects are male. Liara will reveal that her assistant provided her the information. Following the conversation, you can return to Liara. It turns out the assistant had been the Observer the entire time, and Liara never knew. You can only reveal that it was the assistant by visiting all of the locations in the markets and finding out that the one in the message is female, helping Liara even further by correctly guessing the Observer's identity.