A Crime Story

Appeared in Volume 9/2, May 1996

An elementary school teacher in New York State had her pulse stolen. The thief had to be Lillian, Judy, David, Theo, or Margaret.

When questioned, each child made three statements:

Lillian: (1) I didn't take the purse. (2) I have never in my life stolen anything. (3) Theo did it.

Judy: (4) I didn't take the purse. (2) My daddy is rich enough, and I have a purse of my own. (6) Margaret knows who did it.

David: (7) I didn't take the purse. (8) I didn't know Margaret before I enrolled in this school. (9) Theo did it.

Theo: (10) I am not guilty. (11) Margaret did it. (12) Lillian is lying when she says I stole the purse.

Margaret: (13) I didn't take the teacher's purse. (14) Judy is guilty. (15) David can vouch for me because he's known me since I was born.

Later, each child admitted that two of his/her statements were true and one was false.

Assumming this is true, who stole the purse?

From the American journal Scripta Mathematica