"We have no evidence" - pure bs and speculation. Yes a trained operator could damage a lot of kinds of hardware with a Barrett or other .50 rifle. Does it make any sense (given the range of tools with which have to apply to solving this problem) to use a sniper to ruin the Norks launch? No. Option 1) this is filler (slow news day at the Washington Times?) or option 2) deliberate misinformation.
During Desert Storm Delta Force and SAS teams behind the lines are well-known to have fired at SCUD missiles from long distances. The bullets ruptured fuel tanks and other vital systems. Most times, the Iraqis didnt even know there had been a shot.
When the scuds were fired, the leaks caused catastrophic failures, which resulted in explosions, Sometimes on the launchers, other times soon after the missiles liften off.