(photo gallery and documents)—WOONSOCKET, R.I. — A year-long investigation by the Rhode Island State Police culminated Wednesday with more than 150 investigators swarming through northwestern Rhode Island seizing guns, drugs and arresting 49 people, many of them associated with motorcycle clubs that authorities feared were trying to establish turf in Rhode Island.

The arrests were made in a coordinated series of pre-dawn raids that involved the use of explosive devices to breach heavily fortified building, an armored truck and battering ram to break down doors; and dozens of heavily armed SWAT team members and other officers, according to State Police Supt. Col. Ann C. Assumpico.

She said the raids were conducted without incident.

The investigation, dubbed Operation Patched Out, began last May after detectives received information that “some of the most violent motorcycle gangs in the country were establishing local chapters in northwestern Rhode Island.”

The state police identified them as members of The Pagans and Kryptmen, who were “allegedly involved in gun and drug trafficking” and well as other illicit crimes.

Through electronic surveillance and court-ordered wiretaps, state police investigators intercepted thousands of phone conversations and text messages while collecting other evidence detailed in a 1,300-page affidavit used to secure warrants for almost 30 different searches.

The investigation revealed that the suspects were involved in “large scale gun and drug trafficking” and the widespread theft of stolen ATVs, lawn tractors, snow blowers and other equipment, as well as “fraudulent mortgage and bank activity,” said Lt. Col. Joseph Philbin.

Assumpico said the operation was believed to be the “single largest takedown in Rhode Island State Police history.”

Philbin, who spearheaded the investigation, said the motorcycle gangs had been involved in numerous acts of violence, including three shootings that had never been reported to law enforcement.

At one point, he said, detectives learned one of the alleged gang members was en route to commit murder. The suspect was arrested at a motor vehicle stop near the alleged victim’s house and detectives seized a loaded 9-mm pistol. The suspect remains held behind bars.

State police spokeswoman Laura Meade Kirk said the operation resulted in the seizure of 53 illegal guns as well as a large quantity of marijuana, crack, cocaine and heroin. Philbin said the authorities also seized silencers and a rocket launcher.

According to a news release, more than 150 law enforcement officers — including members of the state police, along with federal, state and local police agencies — conducted a series of coordinated, simultaneous raids shortly before 4 a.m. Wednesday.

Search warrants were executed at 29 locations in Woonsocket, Burrillville, Chepachet, North Smithfield and Warwick, Rhode Island; as well as Bellingham, Blackstone, Charlton, Milford, Massachusetts.

The arrests included the presidents of the Massachusetts Pagans and the Rhode Island Pagans motorcycle gangs, authorities said.

One leader was charged with more than 230 counts, according to Attorney General Peter F. Kilmartin.