SANTA CRUZ >> The U.S. Department of Homeland Security led a pre-dawn operation across Santa Cruz County and Daly City on Monday, arresting 11 members of the Mara Salvatrucha, or MS-13, gang.

The effort, in partnership with local law enforcement, was part of a five-year investigation into the notorious street gang operating in the area, according to Santa Cruz Deputy Police Chief Dan Flippo. The suspected criminals, members of MS-13, are men between the ages of 20 and 40, he said. A 12th man had been arrested prior to Monday’s operation, Flippo said.

Authorities allege that those arrested had a history of such crimes as murder, extortion and trafficking of heroin and methamphetamine. Two firearms were also seized during the arrests. At least two of those arrested were being held on charges unrelated to gang activity, Flippo said. The detainees were transported to Santa Clara County to face federal court indictment on suspicion of trafficking methamphetamine, he said.

The 12 separate raids, some of which utilized large armored personnel carriers emblazoned with the Homeland Security insignia, sparked panic that Immigrations and Customs Enforcement, or ICE, was conducting raids on undocumented workers. Flippo said he did not know the immigration status of those arrested.

“We want to make it very clear that these were not immigration-related arrests,” said Flippo. “We recognize the timing is unfortunate, but this is a federal criminal case that was five years in the making and has nothing to do with immigration.”

The operation culminates an investigation that first began with the Santa Cruz Police Department in 2011 and ballooned into a federal case when the international MS-13 affiliate’s involvement was uncovered, Flippo said.

“We are very certain that this gang was involved in at least two homicides and another shooting in Santa Cruz,” said Flippo.

Residents in several neighborhoods became aware of the operation through flash bangs and low-flying helicopters with spotlights, beginning at about 4 a.m. On social media, neighbors near 38th, 17th and 7th avenues, Market Street and the Beach Flats neighborhood described raids and law enforcement staging nearby.

“This morning’s raids threw the immigrant community into a panic,” said public sociologist and UC Santa Cruz researcher Paul Johnston. “As far as we can tell there were legitimate law enforcement targets, but Trump’s new mandate to prioritize deportation of a far broader swathe of the immigrant community means many, many more people — parents, families, ordinary working people — must be fearful. Many are now in hiding.”

Under these circumstances, Johnston said, no Department of Homeland Security involvement in local law enforcement is acceptable.

Shortly after the raids, rumors circulated on social media that the operations was associated with the ICE operation that arrested 161 undocumented immigrants in Southern California last week.

A 6:30 a.m., a CBS San Francisco reporter tweeted, “Major Homeland Security/ICE operation in Santa Cruz. Several arrested/detained. Heavily armed agents, cops everywhere.”

Flippo said the city of Santa Cruz and the Santa Cruz Police Department would not participate in an immigration raid and the timing of Monday’s raids were “unfortunate” but in no way connected to an immigration sweep.

“This investigation was ramped up very recently based on the belief that there was a significant threat to public safety,” Flippo said in a release.

Flippo said concerns the raid was an immigration operation were also raised when witnesses reported women had also been arrested in the operation. However, Flippo said those arrested Monday were all men. Women and children may have been detained temporarily at the raid sites while federal agents executed the warrants, but none held further.

MS-13 is an international criminal gang that originated in Los Angeles before spreading to other parts of the U.S., Canada, Mexico and Central America.

City Councilman Chris Krohn, who has been involved with the local Sanctuary Santa Cruz group, said on Monday afternoon that he had received 30 to 35 emails and five phone calls related to the police action.

“I remain anxious in what is turning out to be a scary and extremely worrisome time for many immigrants in our community. Immigrants who were not necessarily the targets in the DHS raid this morning, but none the less honestly fearful,” Krohn wrote in an email. “Given the national scene with Trump wanting to ‘deport Mexicans’ and ‘ban Muslims,’ today’s police action was a frightening scene of what we have been reading about in other places being played out right here on the streets of Santa Cruz.”

Primarily composed of Central Americans, mostly Salvadorans, MS-13 is active in both urban and suburban areas, according to Wikipedia. In the U.S., the MS-13 is prevalent in Los Angeles County and the San Francisco Bay Area, including Santa Cruz County.