From the Maryland ACLU website:
The ACLU of Maryland is defending Anthony Graber, who potentially faces sixteen years in prison if found guilty of violating state wiretap laws because he recorded video of an officer drawing a gun during a traffic stop. In a trend that we've seen across the country, police have become increasingly hostile to bystanders recording their actions. You can read some examples here, here and here.
However, the scale of the Maryland State Police reaction to Anthony Graber's video is unprecedented. Once they learned of the video on YouTube, Graber's parents house was raided, searched, and four of his computers were confiscated. Graber was arrested, booked and jailed. Their actions are a calculated method of intimidation. Another person has since been similarly charged under the same statute.
The wiretap law being used to charge Anthony Graber is intended to protect private communication between two parties. According to David Rocah, the ACLU attorney handling Mr. Graber's case, "To charge Graber with violating the law, you would have to conclude that a police officer on a public road, wearing a badge and a uniform, performing his official duty, pulling someone over, somehow has a right to privacy when it comes to the conversation he has with the motorist."