If you are talking about the US goverment /NSA, they already have been colecting data of everyone in the US (and some in other countries). If you are talking about real legal investigation, ussually when you are a suspect in a crime or if they think you are actnig suspicious (like terrorist suspicious).
The information collected or measured during an investigation is typically referred to as data. This data is used to analyze patterns, draw conclusions, and make informed decisions related to the investigation.
data
observations
observations
To provide a visual representation of the data collected to draw conclusions from the data.
Data that is collected may have been collected previously for some reason, or it might have been collected recently. Data is usually collected to show statistics or information about something specific.
You think probable to a determinatiom.
A reliable investigation will allow you to make conclusions that are supported by the data you have collected,and that reflect the findings of other scientists.
The data collected does not have to be measurable.
evidence
The collected data is organized in a fashion so you can determine if the hypothesis is supported.
In continuous grouped data the data is collected continuously and in groups. Data collected is in class intervals the actual data values are not visible.