Police are investigating thefts of war memorabilia, including a rifle, from two country South Australian RSLs and a museum over the past month.

Boer War and Vietnam War medals and a World War I-era locket were stolen from the Melrose Heritage Museum in the Flinders Ranges a week and a half ago.

Then on Tuesday, a rare set of 1800s “Aboriginal handcuffs” and a grandfather clock key were also stolen from the volunteer-run museum last week.

The handcuffs, which were used by police on Aboriginal people, were smaller than normal and were in the museum’s magistrates’ room.

Museum caretaker Shayne Clark said the thefts were disappointing.

“It’s the few that ruin it for the many,” Mr Clark said.

“The vast majority of our visitors are fantastic and they like seeing what we’ve got to display and respect what we’ve got, but occasionally we have people come through who will pick up whatever isn’t bolted down.”

The locket and medals were on loan and had sentimental value well beyond their monetary worth, Mr Clark said.

“It’s just tragic because people are genuinely trying to do the right thing and display things that have significant historical value,” he said.

“It’s really sad when their generosity gets abused and people take what’s not theirs.”

The museum will consider installing CCTV cameras.

This WWII air raid siren went missing from Port Victor RSL. Photo: SA Police

Also in country SA, a deactivated World War I Lee-Enfield .303 calibre rifle with a bayonet attached was stolen from the Cowell RSL between September 27 and October 1.

Police say thieves broke into the club on Third Street and stole the firearm along with cash, alcohol and six World War I bayonets.

“The community as a whole is in shock over the whole thing,” Cowell RSL president Robert McFarlane said.

“Every item has got a story behind it and I would hope to appeal to them that they return the stuff.

“To us it’s priceless and the amount of money they’ll get for it if they try to sell it is only peanuts — it’s virtually irreplaceable.”

Between August 31 and September 23, a World War II air-raid siren and a Vietnam War soldier’s slouch hat were stolen from the Port Pirie RSL war museum display. No-one has been arrested over the thefts.

Thefts hurt the whole community

University of Adelaide military history professor Robin Prior said stealing military memorabilia made it harder for Australians to learn about history.

“A lot of people find out about war by visiting museums,” Professor Prior said.

Light-fingered visitors have stolen relics from Melrose Museum. Photo: Melrose Museum

“They do make it easier for people to transfer them back to those times, when the fighting was taking place.

“It’s particularly disturbing just about a month before Remembrance Day that these things have been removed.”

He said the thefts showed a lack of respect for Australia’s military history.

“Soldiers fighting for this country used those weapons or wore that hat,” he said.

“I think it is disrespectful to steal. They were given by the person who wore them or by the family, for public display, as an act of generosity.”

Police arrested two men on September 15 and 16 over the alleged theft of a deactivated antique firearm and a deactivated antique flare gun from the Victor Harbor RSL on September 9. The stolen items have not been recovered.

-ABC