"While one of them stole her purse, the other two grabbed her hair, twisted it into a long pony tail and in a matter of seconds cut it off," police inspector Alcides Iantorno said Thursday by phone.
Marchet, a saleswoman, told police she'd been growing her long black hair for four years. Iantorno said the thieves, who are still at large, were probably hoping to sell the hair to wig makers or to hair-transplant centers.
"They must be thinking the hair is worth a lot of money," he said. "But they are in for a surprise because the market is glutted with cheap human hair imported mainly from India."
The incident, which occurred Wednesday evening in Rio's low-income Vicente de Carvalho district, left Marchet "traumatized and feeling naked," Iantorno said.
"I am very sad. I can't even look at myself in the mirror," she told the O Estado de Sao Paulo newspaper. "Apparently they knew what they were doing because my friends tell me the haircut came out pretty well."
If caught, they will be charged with armed robbery, which carries a maximum sentence of 15 years, Iantorno said.
He said a similar case occurred more than a year ago in Ilha do Governador, a district several miles away.