Los Angeles police say two sisters have been arrested on suspicion of medical malpractice for allegedly running an illegal cosmetic fillers business in the Sylmar area.

Police said Tuesday that Guadalupe Viveros and Alejandra Viveros were taken into custody Monday morning.

Police say they are accused of practicing medicine without a license. Each is being held on $20,000 bail.

Police began an investigation after alleged victims told authorities they'd become ill after being injected with the fillers, usually in the face or buttocks.

In some cases, police say the fillers hardened into solid plastic and the patients developed infections.

Detectives say Guadalupe Viveros claimed to be a physician in Mexico, but is not allowed to practice medicine in the United States.