Researchers have uncovered two hidden layers beneath a Pablo Picasso painting from his Blue Period and traced the casting of several Picasso bronzes to “rogue” foundries operating in occupied Paris during World War II.

Determining if a fire is accidental or due to arson is a process often plagued by poorly understood science, subjective judgments on the part of investigators and inadequately trained personnel, according to a new AAAS report on the quality of fire investigation in the United States.