An accused illegal alien serial killer who has been charged with murdering 12 elderly women overstayed his visa, was never deported, and was able to obtain a green card.

As Breitbart News reported, 46-year-old illegal alien Billy Chemirmir, born in Kenya, had been living in Dallas, Texas when he was originally charged in March 2018 with murdering 81-year-old Lu Thi Harris.

This month, thowever, Chemirmir was charged with murdering 11 other elderly women, all between the ages of 76 to 94-years-old. The illegal alien worked as a home healthcare worker and was a home aide to many of the women.

A law enforcement source confirmed to Breitbart News that Chemirmir first arrived in the U.S. on a B-2 visa — commonly known as a tourist visa — in July 2003. Though Chemirmir was supposed to only temporarily be in the U.S., he overstayed his visa and became an illegal alien who was eligible for deportation.

Rather than being deported, however the illegal alien was able to use a loophole in the country’s legal immigration system that allowed him to obtain a green card after marrying a U.S. citizen.

In November 2007, Chemirmir was approved for a green card allowing him to permanently resettle in the country. Every year, more than 1.2 million legal immigrants are admitted to the U.S.

A law enforcement source also said the illegal alien had a criminal record, including convictions for drunk driving, trespassing, assault, and obstructing a police officer.

Chemirmir has been formally charged with the string of murders of elderly women across the region, but police have said that there could be more victims. Currently, investigators are looking into about 750 deaths of elderly women in the area.

Chemirmir has remained in custody since last year on a $1 million bond.

As of March, there were more than 415,000 illegal aliens in the U.S. who had overstayed their visas. This includes more than 300,000 illegal aliens who arrived in the U.S. from countries that are not part of the Visa Waiver Program, which allows certain nationals to come to the country for up to 90 days without obtaining a visa.

In total, 20 foreign countries have visa overstay rates that exceed ten percent. About 40 percent of the 11 to 22 million illegal aliens living in the country came legally and overstayed their visas, according to the Center for Immigration Studies.

John Binder is a reporter for Breitbart News. Follow him on Twitter at @JxhnBinder.