Weston's plea follows that of Stephanie Foulke, 22, who pleaded guilty Nov. 25 to the same two charges.
Foulke testified for the prosecution at Tolbert's Nov. 6 preliminary hearing, describing in detail the death and dismemberment of 40-year-old Francis Zarzycki of Northeast Philadelphia.
Authorities say Tolbert lured Zarzycki on Aug. 26 to his Center City apartment at 11th and Locust Streets to meet and party with the two prostitutes. The real plan, however, was to rob Zarzycki, who was believed to be carrying large amounts of drugs and cash.
Foulke testified that the plan went wrong from the start. While she and Weston entertained Zarzycki, Tolbert crept in from another room and punched him from behind.
Zarzycki, however, began fighting back and screaming, leading Tolbert to use a Taser on him and sit on his back while the women tied him up. Foulke said that Zarzycki stopped breathing and that Tolbert's panicked efforts at resuscitation failed.
Authorities say Tolbert dismembered the body, wrapped the torso in plastic, and dumped it into the Schuylkill. The torso was found Sept. 3 off Grays Ferry Avenue. The head and limbs have not been recovered.