PORTLAND — The Maine State Police should explain whether it is using social media to monitor what the public says online, according to a state representative who is calling for a public hearing.

A member of the state legislative committee that oversees law enforcement said he could not recall the state police briefing him on its use of Geofeedia, a controversial computer program that monitors public activity on social media. Two law enforcement officers told BDN Portland last week that the Maine State Police has purchased a license for the service.

“I would be interested in having a public hearing on how [Geofeedia] is being used on the state level and its overall effectiveness,” said State Senator-elect Justin Chenette, D-Saco, who sat on the Criminal Justice and Public Safety committee as a state representative for the last two years.

Since 2014, the South Portland Police Department has used Geofeedia to monitor public chatter on sites like Twitter and Facebook. The program was developed with funding from the CIA and can pinpoint a social media user’s location.

Chenette called the state police’s lack of transparency “troubling.”

He and other lawmakers said that Mainers need more information about social media surveillance.

“We must all realize that when we post or tweet something online it becomes public and anyone can access that information whether it be police or criminals,” said Chenette. “Our law enforcement officials are simply trying to keep up with the rapidly changing environment we now live in.”

Every member of the committee and South Portland City Council who responded to requests for comment said that they were unaware of Maine police monitoring social media before BDN Portland’s report on the issues, although multiple members of each body did not respond. Several said they didn’t have enough information about the program to form an opinion.

Criminal Justice and Public Safety committee chair Rep. Lori Fowle, D-Vassalboro, did not respond to repeated requests for comment and co-chair Senator Kim Rosen, R-Bucksport, declined to comment. New members may be appointed to the joint committee during the next legislative session in January.

Although previously little known in Maine, Geofeedia and other similar programs have become the center of a national debate over policing and privacy rights online. Many police departments across the country surveil social media, and police contend that they are merely listening to things said in public. First Amendment watchdogs, however, argue that surveillance has a chilling effect on free speech.

Following harsh criticism of police using Geofeedia to monitor protests and demonstrations, Facebook, Twitter and Instagram in October cut the Chicago-based company off from their data.

South Portland police said that they use Geofeedia to scan for keywords that might signal a public safety risk, like “gun” or “suicide,” but mostly get false hits. Geofeedia has cost South Portland $13,500, which was mostly paid for through a grant, according to the police department. City councilors said they were previously unaware of the program and are divided in their views.

“There can be no expectation of privacy in a public space,” said councilor Claude Morgan, who likened police watching public web chatter to the video cameras South Portland has trained on the road leading up to the Casco Bay Bridge.

But using Geofeedia “seems to run opposite [to] the department’s commitment to community policing,” according to South Portland City Councilor Eben Rose.

Outgoing South Portland M ayor Thomas Blake said he was unfamiliar with the social media surveillance program and had asked the city manager to prepare a briefing on it.

In Boston, the City Council is scheduled to question the local police force this week about its planned use of similar technology.