BANGKOK, Thailand — Few weapons marry convenience and raw power like the M-79 grenade launcher. Known to Vietnam War-era G.I.’s as the “Blooper,” it can lay waste to cement walls or crowds only to discretely vanish into an attacker’s backpack.

Throughout the past two years in Bangkok, this 28-inch menace has done just that. Just as Anthrax letters evoke post-9/11 paranoia in America, the Blooper has come symbolize politically motivated terror in the Thai capital.

M-79 grenades recently fired on army and government buildings have revived the threat of Blooper attacks in Bangkok. Since 2008 the city has seen roughly a dozen M-79 incidents, which have killed one and injured nearly 100.

Each attack has targeted symbols of Thai elitism, power or aristocracy. While the assailants’ message of intimidation is clear, their identity is not. Authorities have yet to convict anyone for these M-79 strikes.

Easy to conceal, and available on the black market, the Blooper is a natural hit-and-run weapon for saboteurs, said Surachart Bamrungsuk, a political scientist with Chulalongkorn and instructor at Thai military academies.

“You need only a little training to use the M-79. But once you’re friendly with it, this is a weapon that’s very easy to use,” Surachart said. “It’s also easy to find.”

America introduced hundreds of thousands of M-79s to Southeast Asia in the 1960s — and many still remain. It has earned the deceptively cute “Blooper” nickname for its odd firing sound: an aspirated “ploomph” as the grenade sails out of the stubby barrel.

For Vietnam-deployed G.I.s, the weapon offered the power of a mortar round in a six-pound, shoulder-slung gun. It later landed Hollywood cameos. Arnold Schwarzenegger toted a Blooper in the "Terminator" films and an M-79 is also featured prominently in a haunting, profanity-laced scene from the war epic "Apocalypse Now."

After Americans pulled out of Vietnam, left-behind M-79s continued to surface in Thailand’s 1970s communist insurgency and Cambodia’s 1980s Khmer Rogue killings. Even today, tourists can shoot old Bloopers at firing ranges near Phnom Penh.

But in modern Bangkok, the M-79 has resurfaced in a specific context: terrorism toward political targets. Its grenades have been fired at pro-establishment protesters, the prime minister’s compound and Army headquarters — but never at the public at large.

Around midnight on Feb. 13 an M-79 grenade exploded in a parking lot near the premier’s head office, damaging cars but leaving no injuries. In January an M-79 grenade soared over the Royal Thai Army headquarters gates late at night, detonating nearby unoccupied rooms on the sixth floor, according to the military.

However, the Blooper has also killed and maimed. An urban protest faction known as the “yellow shirts,” who personify elitism in the eyes of many upcountry Thais, have endured most of the attacks.

The yellow shirts coalesced in 2005 to drive out ex-Prime Minister Thaksin Shinawatra, accused of pervasive corruption and buying rural votes. They succeeded the next year when Thaksin was ousted via military coup, and stuck together to rally against other politicians they’ve labeled as corrupt.

Their aggressive protests have also placed them in the line of fire. In last year’s assassination attempt on the faction leader, media mogul Sondhi Limthongkul, his van was peppered with roughly 100 M-16 bullets. An M-79 grenade was also aimed at his vehicle, but failed to explode and harmlessly rolled under a nearby bus.

Sondhi was also targeted by an M-79 grenade during a 2009 speech. It missed his stage but injured at least 12 crowd members. Yet another guns-and-grenades assault on his TV station the year before sent a news anchor scrambling from his desk on live television.

The worst rash of M-79 attacks came in 2008, when the yellow shirts carried out a long-running occupation of government offices and two Bangkok airports. An estimated seven attacks on their rally sites injured at least 75 protesters, leaving many maimed and at least one dead.

But throughout the entire two-year spate of Blooper attacks, authorities have only implicated one man — a wayward 58-year-old Thai army general who claims a history of killing communists with the help of the the CIA. He has more recently become a figurehead for Thais disdainful of what they call the “privileged class.”

Maj. Gen. Khattiya Sawasdipol, a suspect in the M-79 attack on army headquarters, was charged with owning illegal weapons including M-16 bullets and M-79 shells after police raided his home and the home of one of his associates. Khattiya has denied involvement in the incident.

Khattiya claims to be admired as a battle-proven, hands-dirty swashbuckler by many in the Thai army’s rank-and-file. He openly mocks the top brass, proudly maintains a private militia and has threatened to fight tanks with molotov cocktails if the military stages a future coup.

No matter the mysterious attackers’ intent, more M-79 attacks could give military leaders pretext for a crack down against their critics, said Suranand Vejjajiva, a cousin to the Thai prime minister and political commentator.

This is especially relevant, he said, as Bangkok faces more unrest. A bloc largely representing ruralites and the urban working-class — called the “red shirts” — plan to gather 1 million Thais in mid-March to topple the government, demand new elections and end what they call “aristocratic rule.”

In light of the recent M-79 attacks and looming protests, the current ruling party has readied soldiers and police for riots. Any violence from the red shirts, Suranand said, could inadvertently trigger the restoration of order by force.

“A bomb thrown here. An M-79 shot there. If some blood lets out, there will be an excuse for stopping the process of democracy here in Thailand,” he said. “That worries me.”

Related Stories