The phrase "と見て" in Japanese is used to indicate a judgment or assessment of a situation. It's similar to the English expressions "to view as" or "to regard as." In the context of your translation, it seems to be used in a news report or a similar formal context.
Let's break down the specific sentence:
Translated, this would be:
"Based on the method of the crime, the Sakurami Police Department"
"considers it to be an act committed by the same serial perpetrator who has been targeting Sakurami Town,"
"and plans to set up an investigative headquarters to start a thorough investigation."
So, "と見て" in this context is used to express the police department's assessment or view that the crime is linked to a series of similar incidents in the area. It's a formal way of stating an opinion or judgment, often used in official statements or reports.