As the government threatens to prosecute those who speak out against the maps it uses to demarcate the border with Vietnam, one opposition lawmaker says he has found a map in the United States’ Library of Congress that he claims could shine new light on the issue.

“These maps do not have Vietnamese stamps like the government maps do,” Cambodia National Rescue Party lawmaker Um Sam An said in an interview yesterday.

“I will take it for verification [to Cambodia] so we can know which maps are correct and which maps are incorrect.”

Sam An, who has been in the United States on a fundraising tour since May, said he believed the 26-piece map he found was one of the original maps submitted to the United Nations by King Sihanouk in 1964.

The government says it is using that same map. But some members of the opposition have claimed in recent months that the government’s maps favour Vietnamese border claims.

Sok Touch, the head of the National Border Committee, yesterday strongly denied that the stamps on a map mattered.

“The stamp is not important. What is important is if these maps are incorrect or not,” he said.

Hun Sen said in a speech this Wednesday that anyone accusing the government of using “fake maps” would face legal action with “no tolerance”.

Touch, however, said he still welcomed Sam An’s submission, although he didn’t believe the map he found was the original Sihanouk map as claimed.

“So bring the [maps] to verify,” he said. “If it is good or bad, we will see.”

The ruling Cambodian People’s Party has not taken kindly to opposition criticism over the border.

Sam Rainsy Party Senator Hong Sok Hour was arrested on August 15 and charged with treason for posting an allegedly fake section of a 1979 border treaty with Vietnam on Facebook.

But that doesn’t appear to have fazed Sam An, a longtime campaigner on the border issue who posted photos of himself with the map on his Facebook page.

Sam An said that he planned on returning to Cambodia by the end of September, although he would first verify the Library of Congress map by personally going to the United Nations library.

Following a request from Prime Minister Hun Sen, the UN handed over maps of Cambodia to the government last week which – although not King Sihanouk’s originals – were quickly used to demonstrate that the government’s mapping was sound.

However, Sam An cast doubt on the government’s map by claiming yesterday that it was stamped by Vietnam and signed by current Supreme Court justice Dith Munty during a delimitation treaty in 1985.

Var Kimhong, the senior minister in charge of border affairs, declined to comment yesterday, saying that Um Sam An’s map was “nothing new” and that he was in a meeting.

The CNRP has distanced itself from the maps issue recently, saying individual lawmakers’ views on the border are their own and not the party’s.

Reached yesterday, CNRP spokesman Ou Chanrith declined to say if the party supported Um Sam An’s latest finding.

“He [posted] this on his Facebook,” he said. “The CNRP hasn’t discussed or talked with him yet.”

ADDITIONAL REPORTING BY CHARLES ROLLET