AP Photo

Over 50 fires gutted cars in Los Angeles this past weekend. While most of the damage was limited to vehicles, some of the flames caused destruction to adjacent property, including to a home that once belonged to Jim Morrison. LA has not experienced this many fires since the 1992 riots. On Monday police detained a person of interest, 24-year-old German national Harry Burkhart, who was seen on security footage near one of the fires.

While some people start fires for insurance money or to cover up crimes, arsonists set fires to feel control—and, in many cases, sexual excitement. Profilers say arsonists have few close relationships; they start blazes to feel important. Many only have a high school education, but some of the most prolific showed a surprisingly high...