After going through the Boulder Citizens’ Police Academy a number of years ago, I joined the alumni association, which holds meeting once a month with interesting guest speakers. This week Detective Chuck Heidel spoke on the Marty Grisham cold case. Mary Grisham was murdered in 1994. Through perseverance and hard work, Detective Heidel solved the case, and Michael Clark was brought to trial and convicted in 2012. Although no one witnessed the murder and the police never found the weapon, the District Attorney and police build a solid case using only circumstantial evidence. The judge made a statement to the jury that the law makes no distinction between direct and circumstantial evidence, and in this case, the circumstantial evidence led to a conviction.