Quash, of Laventille, is expected to virtually appear before a Port of Spain magistrate today.
Another man who had been detained with him has since been released pending further enquiry.
Police said yesterday the charges against Quash include that on a day unknown between November 29 and December 5 at Upper La Canoa Road, Santa Cruz, together with other persons he murdered Ashanti Riley.
Quash is also charged with assaulting a 16-year-old girl on March 14 this year at Bagatelle, San Juan.
Ashanti was reported missing on November 29. On December 4 her battered, partially decomposed body was found in a river off Upper La Canoa Road, Santa Cruz.