LOS ANGELES  --  Law enforcement officials this morning arrested 18 defendants named in three federal indictments stemming from an investigation into South Los Angeles street gangs that took more than two years.

The gangs were allegedly controlled by an imprisoned Mexican Mafia member who ran criminal activities through his daughter, according to the U.S. Attorney's Office.

The investigation focused on the activities of the Harpys street gang, which claim a territory southwest of downtown Los Angeles and north of the University of Southern California, federal officials stated.

Mexican Mafia member Danny Roman allegedly controlled the Harpys, which is known as the Harpys-Dead End gang,  along with a dozen other Hispanic gangs of South Los Angeles, federal officials stated.

Roman gave his daughter and son-in-law orders to tell gang members to engage in criminal conduct including collecting "taxes" from businesses and gangs that are sent back to Roman in state prison, according to federal authorities.

The gang enforces the collection of "taxes" through threats of violence, including murder, for any business or gang that fails to pay or reports the collection of taxes to police.

In addition, Roman and the Harpys gang were allegedly involved in the distribution of methamphetamine cocaine, cocaine and crack cocaine and heroin, the murder of a gang member who owed a debt to another gang member, say federal officials.

The indictment accuses Roman of orchestrating the extortion of vendors at the Alameda Swap Meet, which has been a central location for criminal activity by gang members of the 38^th Street gang who are also under Roman's control, federal authorities allege.

During the course of the investigation tabbed Operation Roman Empire, federal officials stated that investigators seized about eight and a half pounds of methamphetamine, a half-pound of heroin, a pound of cocaine, 23 pounds of marijuana and 22 guns.

Also 10 children were removed from several residences by the Los Angeles Department of Children and Family Services' Multi-Agency Response Team, according to federal authorities.