Matthew Engler (Scott Speedman) used his power, money, and technology to gather a ton of video and photo evidence of the happenings throughout Madre Linda.
Although he ultimately deleted his files following pushback about how this information would negatively impact his company, it's not all gone.
Matthew's son, Theo (Dylan Arnold), copied some of the files onto a flash drive at the end of season three.
Although Matthew deleted the files he had, did he continue to collect data and spy on the city afterward? Considering he lived next door to the Quinn-Goldbergs, did he get footage that could prove Joe (Penn Badgley) framed Love's (Victoria Pedretti) murder-suicide and fled Madre Linda?