Peruvian officials say there are "strong indications" that a rogue group of officers within the country's police force has carried out illegal killings.
Deputy Public Order Minister Ruben Vargas said an investigation had identified at least 18 members of the force who were allegedly involved.
The investigation suggests the group was behind the killing of at least 20 civilians since 2012.
A general is among the police officers suspected.
Mr Vargas said at a news conference that the case resembled that of the "false positives"
in Colombia, in which soldiers killed civilians and then passed them off as left-wing rebels to falsely boost the number of rebels they had "neutralised".
In the Colombian case, the soldiers were at first rewarded with days off and other perks before the scandal emerged and a number of those involved were sentenced to lengthy prison terms.
In Peru, the rogue officers allegedly passed the victims off as dangerous criminals to secure promotions.
The killings happened in at least six different police operations in the capital, Lima, in the northern town of Chiclayo and in two instances in Chincha Alta.
Mr Vargas said that 11 of the 20 people known to have been killed did not have any criminal records.
He accused the police officers of falsifying intelligence reports to fit their stories.
One of the officers under investigation was decorated six times for his service, the minister said.
Those involved have not been named.
Source: BBC News