![DEREK MICHAEL MASON](https://assets1.cbsnewsstatic.com/hub/i/r/2024/06/24/475f9f7b-049a-4812-bb72-58063e355efe/thumbnail/640x360/854467f4d7ccc14499148b0f7e776216/copy-of-720p-web-thumbnails-1.jpg?v=a23cb4bdf4fa7f3cb72e5118085577f9#)
Philadelphia man identified in decades-old cold case, PSP, Lancaster County DA's Office say
There's been a crack in a decades-old cold case. Derek Michael Mason's remains were found in Lancaster County in 1992, but he was last seen in West Philadelphia in 1991.