The gang, which authorities named the “Soulless Human Traffickers”, preyed on poor pregnant women and persuaded them to give up their babies, the office added in a statement released on Tuesday.
A five-month-old baby was also rescued in an early Tuesday police raid on 18 properties in the southern city of Arequipa, officials said.
Those arrested included Becerra and 13 others, including a paediatrician and a gynaecologist, who were accused of being members of the criminal group.
The investigators suspect Becerra’s partner, Cintia Tello, to be the ringleader of the gang. Reuters news agency said it could not reach Becerra and Tello for their comments.
Authorities allege the babies were sold for 4,000 Peruvian soles ($1,190).
An investigation has been launched to find out whether the babies were sold to foreign couples, the BBC reported.
Becerra became head of Peru’s national police force in November 2010 during the government of former president Alan Garcia.
He served about a year and was replaced in October 2011, after a subordinate accused him of sexual harassment, according to local newspaper El Comercio. Becerra had denied the allegations.