## How Mathematics Solved a Real Murder

A woman was found dead at the bottom of The Gap at Sydney’s Watson Bay in 1995. It wasn’t until 1997 that University of Sydney physicist, Rod Cross, was asked if the victim could have jumped off the cliff. In 1998, the coroner declared an open finding in the death of Byrne.

It wasn’t until 2003, however, that the police contacted Ross to check the maths. He said that she couldn’t have slipped or jumped. The case was reopened and in 2006 Byrne’s ex-boyfirend Wood was arrested in London and eventually found guilty of her murder. Wood was sentenced last year to 17 years in jail with a non-parole period of 13 years.

Why we are interested in this case, mathspigs, is because Cross, The Physicist, made the comment when asked during the trial that the maths involved was not rocket science but maths high school students would be able to master. Can we?

Solving the problem requires a relatively simple calculation with parabolas.

There is a book coming out this month based on the case, Evidence for Murder: How Physics Convicted a Killer by Rod Cross.

(Tip of the hat to simonjob.)

### 3 Responses

1. This same problem was featured in two fictional TV shows as well:

A recent Season 4 episode of Heroes, where a character’s college roommate apparently commits suicide by jumping out of a window. The character, who can heal herself rapidly, duplicates the fall in order to test whether it was a suicide or not (it was).

A Season 1 episode of the CBS crime drama Numb3rs, called “Structural Corruption” involves the same problem as well. Here’s a lesson plan about the problem from TI:

http://education.ti.com/educationportal/activityexchange/Activity.do?cid=US&aId=7721

• Nice, thank you!

It’s interesting the real life version was actual murder, while the two fictional variants are twists.

Also, the TI lesson plan does seem to suck the life out of the lesson somewhat. I’d at least want the students to experiment with pencils or some other object (“people”) getting pushed off desks (“cliffs”).

2. This will give some impetus to the fact that math is not as abstract as some people think it to be.