Typewriting Analysis

If a crime communicates using a typewriter or a computer printer, it may be possible to identify which machine was used. A typed letter demanding blackmail money or instructing someone where to find a kidnapping victim could be traced back to a suspect’s typewriter or compuer printer. Try the following activity to investigate how detectives analyze typewriting to solve crimes.

Materials

- pencil
- paper with typing on it from several sources, such as papers your friends and family members have typed using different typewriters and computers
- scissors
- glue
- 3-by-5-inch (7.5-by-12.5-cm) index cards
- magnifying lens

Procedure

1. Use the pencil to number all of the typed pages yopu’ve collected.
2. Use the scissors to cut several words out of each page. Glue the words on the index cards, using a separate card for words taken from each page.
3. Record the number of the page the words came from on each card.
4. Use the magnifying lens to obeserve the words on each card. What do you notice about each? Compare the same letter, such as e or a, on each card. How are the letters different?

More Fun Stuff to Do

Have a helper cut a word from one of the pages while you look away. Try to determine which page the word came from by comparing it to your sample cards.

Explanation

Few people write letters on typewriters today. Word processors, computers, and printers have made writing letters much easier. Even so, there are differences between how a letter is made by each machine. By looking carefully at those differences, detectives can determine which machine wrote a certain letter.

Detective Science in Action

In a famous spy case in 1950, Alger Hiss was brought to trial for passing secret documents to the Soviet Union. Hiss was convicted of perjury (lying while under oath), largely because of the evidence that involved his typwewriter. Typed documents taken from a Soviet spy contained valuable information from the U.S. Styate Department. The typing on these documents matched Hiss’s typewriter, which had rather unusual print. The prosecution claimed that Hiss had used the typewriter to copy State Department documents that were later given to secret agents from the Soviet Union.