A former gang member who founded an anti-violence group called No Guns has pleaded no contest to federal weapons charges.

Hector "Big Weasel" Marroquin, 51, and co-defendant Sylvia Arrellano, 25, entered pleas Thursday for three counts of manufacture, distribution and transport for sale of an unlawful assault weapon.

Arrellano also pleaded no contest to machine gun conversion and possessing a silencer and acknowledged that the crime was committed for the benefit of a criminal street gang.

She was given until Tuesday to surrender for sentencing and would likely be sentenced to four years in prison, prosecutors said.

Marroquin attorney Patrick Smith did not immediately return a phone message seeking comment Thursday. No phone listing was available for Arrellano.

Marroquin was arrested in June at his Downey home following a nine-month investigation into weapons sales by the 18th Street gang, to which he once belonged.

Arrellano was arrested at a Cudahy home as a result of the same investigation

Marroquin founded No Guns in 1996, ostensibly to reduce gang and gun violence. The group received $1.5 million from the city as a subcontractor on anti-gang efforts but its contract was canceled last year after authorities learned that Marroquin had hired relatives, including his son, Hector "Little Weasel" Marroquin.

The son is an acknowledged 18th Street gang member who pleaded no contest in June 2007 to home-invasion robbery and was sentenced to nine years in state prison.