A string of apparent arson attacks that have hit construction sites for houses and apartments in Tama, western Tokyo, indicate that someone has a perverse desire to upset the incoming owners, an expert on criminal profiling said Monday.

"Houses under construction are a symbol of happiness and success," said Masayuki Kiriu, a professor of criminal psychology at Toyo University.

"The fact that the culprit is targeting those houses possibly means that he or she is for some reason jealous of the success of the incoming owners," he said.