The thieves have stolen 150,000 reais ($80,645) worth of hair from six salons over the last two months, the Sao Paulo state police said.
In most of the robberies, several assailants entered the salon pretending to be clients, followed quickly by armed accomplices, Inspector Ricardo Prezia told reporters.
He said investigators find it puzzling that the gang is only interested in natural hair and leaves computers, cash and clients' jewellery untouched.
Detectives suspect the group has been tasked to steal the hair for resale elsewhere in Brazil or abroad, Prezia said.
The vogue for hair extensions has led many low-income Brazilian women to sell their locks to salons.
Published 28 December 2011, 00:32 IST