The entire chapter of the Bakersfield, California, Hells Angels Motorcycle Club was arrested as part of a kidnapping, robbery and assault probe, authorities said Tuesday.

Those arrested included five active members of the club’s Bakersfield chapter, as well as two others who are members of Sons of Hell, a motorcycle club that answers to the Bakersfield Hells Angels chapter, the Kern County Sheriff’s Office said in a statement.

Law enforcement officers seized 25 firearms, an unspecified number of rounds of ammunition and gang regalia, according to the statement, jointly released with the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives.

The arrests, which took place Tuesday morning, were the result of a joint investigation by the ATF, the sheriff’s office and the California Highway Patrol. The investigation continues, the agencies said.

One of the seven suspects, John Vaughn, 37, was already in custody as a result of “other charges,” according to the statement. All the suspects so far are said to be from Bakersfield.

The others arrested were named as Ricardo Alvarez, 42; Armando Villasenor, 55; Joseph Soto Sr., 57; Joseph Soto Jr., 33; Joshua Zavala, 31; and John Seeger, 57.

Vaughn and Seeger are members of Sons of Hell, according to the statement; the rest are said to be members of the Bakersfield chapter of the Hells Angels.

They have not been formally charged.

Allegations leading to the arrests include kidnapping, robbery, making criminal threats, false imprisonment, assault with a firearm, participation in a criminal street gang, criminal conspiracy, intimidating a witness or victim and elder abuse, law enforcement said in the statement.

It wasn’t clear whether the investigation stemmed from a single incident or a rash of incidents. Kern County sheriff’s spokesperson Lori Meza said details can’t yet be revealed because the probe is ongoing.

It’s not clear whether the suspects have retained counsel. The public defender’s office for Kern County did not immediately respond to a request for comment.

The U.S. Justice Department designates Hells Angels, founded in the years after World War II in Fontana, California, as an outlaw motorcycle gang and criminal enterprise.

Its colorful history includes members’ attacks on concertgoers at Altamont, California, in 1969, its love-hate relationship with the late author Hunter S. Thompson and its deadly clash with members of the rival Mongols in Laughlin, Nevada, in 2002.

Federal authorities allege the gang has long been involved in trafficking drugs and firearms.

This article was originally published on NBCNews.com