A Medford woman and a Woburn man were indicted by a grand jury on Wednesday for their involvement in a massive human trafficking and money laundering ring, according to Attorney General Martha Coakley.

On Wednesday, Xiu J. Chen, 32, of Medford, and Ronald Keplin, 57, of Woburn were each indicted on six counts of sex trafficking, six counts of prostitution, and six counts of conspiracy to traffic persons for sexual servitude. Chen is also charged with five counts of money laundering, while Keplin has been charged with one count of money laundering, according to court records. 

The Attorney General's office said Chen and Keplin were involved in a sex trafficking ring that spanned Bedford, Billerica, Medford, Reading, Wilmington, and Woburn. The two were arrested on May 13. 

They will be arraigned in Middlesex Superior Court at a later date. 

To learn more about sex trafficking in Massachusetts, read WGBH News' investigative report here