Anchorage police have temporarily stopped providing an on-air feed of their activities following several armed robberies in the past four days.
Police spokeswoman Anita Shell said Wednesday that scanner traffic, which is encrypted over the air but typically available to the public and the media online through free scanner website Broadcastify, won't be resumed "until further notice."
"We don't want the bad guys to hear what we're doing," Shell said.
According to Jennifer Castro, the department's communications director, the decision was made to cut the public feed Tuesday afternoon in response to a total of six reports of armed robberies since Saturday morning, all of which remain under investigation by police.
During three Saturday incidents between about 4:40 a.m. and 10:40 a.m., an armed man with a handgun demanded money at a South Anchorage Holiday gas station and at Arby's and McDonald's restaurants in East Anchorage. Cash was taken from the Holiday and the Arby's, with employees at the restaurant held in a freezer, but a McDonald's employee confronted at a drive-thru window backed away and the suspect ran.
Castro said police also responded at about 8 p.m. Monday evening to a second Arby's location in Eagle River, at 11716 Old Glenn Hwy.
"It was reported to police that there was a robbery with a male suspect that was armed with a gun," Castro said. "The male entered the store, demanded money and left the store."
Castro said callers didn't see whether the man, whose face was concealed during the robbery, left on foot or in a vehicle after stepping outside.
At about 11:30 a.m. Tuesday, two armed suspects demanded money at a Money Mart payday loan store on DeBarr Road, police said. Roughly 90 minutes later, dispatchers got a report of two armed men robbing the Value Liquor store at 7141 Jewel Lake Road.
Castro said the temporary scanner shutdown was initiated hours before police fatally shot a man armed with a knife in an apartment at West 32nd Avenue and Arctic Boulevard on Tuesday evening.
Concerns about the balance between openness and security in access to online scanners were stoked by the Boston Marathon bombing aftermath in 2013, when scanner traffic led some news outlets to inaccurately identify two people as suspects in the attack. Amid the backlash, other U.S. police departments considered fully encrypting their communications.
Asked Wednesday if investigators have found any links among the Anchorage robberies, Shell said only that no arrests have been made in any of the cases.
Dr. Allan Barnes, a University of Alaska Anchorage justice professor who worked as a police officer in two Missouri towns during the 1960s and 1970s, said he remembered criminals using scanners -- which at the time were more cumbersome, "table-based" pieces of technology -- to monitor their own attempts to misdirect officers.
"False alarms would be used to pull police from areas where they could rob gun stores or their favorite liquor store," Barnes said.
The advent of apps that can turn any smartphone into a handheld police scanner helps criminals in diverting officers away from crimes, according to Barnes, which undermines the deterrent value of officers being spread across a community.
"It makes it so much more simpler to do that," Barnes said. "That gives them greater confidence that in the areas where they believe police are less concentrated, they would be safer to commit crimes."
On the positive side, Barnes said, an active police scanner enhances community involvement in police work, by aiding media coverage of police activities and citizens' knowledge of cases in which they may have information to contribute.
"Having the police scanners available to the general public allows greater public involvement in policing itself," Barnes said. "Involving the community in the public activities of the police department ... is very commendable."
While officers have other, more secure means of one-to-one communication ranging from radios to messages on their in-car computers, Barnes said the ability to safely monitor all nearby police activity on a single scanner channel is important to officers' sense of security in the field.
"Your kind of background, of paying attention to what's going on in the community around you, is based on paying attention to when you're called," Barnes said. "You would miss that if you were on some kind of secure channel that only you could hear."
Ultimately, Barnes said, police departments have been tolerant of the move to online scanners because it addresses the public interest.
"I don't know that police were concerned about that because the public probably does have a right to know what the police are doing," Barnes said. "But I don't know if that's an absolute right."