The city's police oversight agency has launched a wide-ranging investigation into how Portland police officers interact with homeless people, a move prompted by The Oregonian/OregonLive's reporting.

The news comes two weeks after the newsroom revealed that one in two arrests made by the Portland Police Bureau in 2017 was of a homeless person, while less than 3 percent of Portlanders are homeless.

"There's a particular concern about the police bureau in profiling people," said Constantin Severe, director of the Independent Police Review.

Following the newsroom's investigation, the American Civil Liberties Union of Oregon called on Mayor Ted Wheeler and Police Chief Danielle Outlaw to investigate whether officers are profiling people who are homeless.

Severe said Outlaw directed the police bureau to ask the Independent Police Review, which is part of the city auditor's office, to conduct an inquiry based on concerns that were raised from the newsroom's reporting and the ACLU. A police spokesman said the chief requested the review after receiving the ACLU's complaint.

The mayor made his first public comments about the newsroom's analysis Monday during an interview with The Oregonian/OregonLive.

The mayor wouldn't provide reaction to the findings but said additional review of police practices is warranted. He said he wants to know how many of the arrests were related to calls from the public as opposed to contacts initiated by police.

"That's of interest to me because probably 80 percent of the calls we get in this office, maybe 90 percent, are people complaining about criminal activity," Wheeler said. "Often times the people committing that criminal activity are homeless, but not always.

"So, the question is, 'Are they arresting people for criminal activity in response to a citizen complaint, or are they proactively going out there and hassling homeless people?'"

The ACLU of Oregon praised the police chief for requesting an investigation.

"We are glad that Chief Outlaw has called for an IPR investigation, and we hope this is the start of the City taking the steps necessary to end the criminalization of homelessness in Portland," Kimberly McCullough, policy director for the ACLU of Oregon, said in a statement. "We also commend The Oregonian for bringing this important information to light."

Police say a lack of housing, mental health and addiction treatment drive the arrests up. They say they've seen a spike in calls to 911 and their non-emergency line about homeless people. Police also increased searches for wanted people at homeless encampments last year.

The Oregonian/OregonLive analysis found that police most often arrested homeless people on property, drug or low-level crimes. The vast majority of the arrests, 86 percent, were for non-violent crimes, the analysis found.

"Does it warrant further evaluation? Of course, it does," Wheeler said. "Certainly, it does."

The Independent Police Review investigates allegations of misconduct against individual police officers but also conducts systemic reviews, said Severe, the agency's director. The group examines whether officers are policing in a constitutional manner and within the bureau's policies.

The investigation into the arrests of homeless people will be one of three to four broader reviews that the agency plans to conduct this budget year, Severe said.

Severe said the police bureau's Professional Standards Division asked for an investigation last week on behalf of the chief. A team of two to three employees will be assigned to it. The team will look at documents, reports and data and talk to experts, police and people who have experienced homelessness.

"Initially, we're going to do a lot of listening," Severe said.

In the past, Severe said, the agency has received complaints from homeless people about feeling targeted by police. The agency, he said, has also received complaints from other community members alleging the police don't take enough action against homeless people who break the law.

He said it's too early to know the precise scope of the investigation and that investigators first need to get acquainted with the issues around homelessness in Portland, before drilling into specific areas. Broadly, they will be probing how police interact with the homeless population.

Severe said he expects the review to take several months but hopes it will be completed by winter.

"We do want it to be timely," he said.

Gordon Friedman of The Oregonian/OregonLive contributed to this report.

-- Rebecca Woolington

503-294-4049; @rwoolington

-- Melissa Lewis

503-221-4316; @iff_or