In the 1995 movie Batman Forever, Edward Nygma (pre-Riddler) knocks out his supervisor Fred Stickley with a coffee pot, ties him to a wheeled chair, and uses him as a guinea pig for his prototype brain-manipulation device. When Stickley tells Nygma he is fired, Nygma pushes Stickley's chair towards the large window at the end of the lab. Stickley partially goes through the window, but because Nygma's device is strapped to his head and attached with a cable, he does not immediately fall. Nygma then removes the device and allows Stickley to fall several stories into the river below, effectively killing him. Nygma then stares directly into a surveillance camera before removing it.
The next day, Bruce Wayne is called into the same lab by Commissioner Gordon, who is investigating Stickley's disappearance. Nygma is shown being interviewed by police and hands them a suicide note from Stickley. Nygma (comically) informs the police that the handwriting, sentence structure, and spelling of the note matches Stickley's exactly, which strongly suggests that Nygma himself wrote the note.
Gordon, Wayne, and a handful of cops are then shown viewing surveillance camera footage of the previous night. The video depicts Stickley running through the lab, laughing maniacally, before jumping through the large window. The video does not show Nygma or anyone else in the lab at the time.
How did Nygma manipulate the security footage to show Stickley jumping through the window? CGI was in its infancy in 1995 so it seems unlikely that someone even as intelligent as Nygma could put together a video clip using such advanced animation, much less be able to mimic Wayne Enterprises' security video well enough to fool the police.