GREENBELT, Md. — Tianna Cosby, also known as “Mendoza,” 24, of Prince George’s County, Maryland, has been sentenced to 114 months in federal prison for leading a large-scale mail and bank fraud conspiracy that defrauded more than 900 individuals and stole over $5 million through altered checks and identity theft.
Cosby pleaded guilty in October 2024 to conspiracy to commit mail and bank fraud and aggravated identity theft. U.S. District Judge Paula Xinis imposed the sentence, which also includes supervised release following her prison term.
According to court documents, from March to August 2021, Cosby led a network of co-conspirators — including Marche Sisco, Tommi Cosby, Biniah Carter, and Zion Adeduwon — who stole more than 700 checks from USPS collection boxes and facilities, including the Washington Network Distribution Center in Capitol Heights, Maryland. These checks were then altered, falsified, and deposited into bank accounts of “account mules” recruited by the group.
Cosby and her co-conspirators used stolen identities, manipulated banking information, and withdrew fraudulently obtained funds through ATMs and digital transfers. The proceeds were laundered through shell companies such as “Santos Detailing” and “Spectrum Dynamics,” both controlled by Cosby.
A search of Cosby’s residence in Woodbridge, Virginia, in January 2024 revealed high-end assets purchased with the fraud proceeds, including 27 designer handbags valued at over $113,000, 14 pieces of luxury jewelry worth nearly $25,000, and a BMW i8 valued at over $114,000. Inside the vehicle, law enforcement found a Louis Vuitton bag containing 151 stolen checks totaling over $610,000.
The case was investigated by the U.S. Postal Inspection Service, the U.S. Postal Service Office of Inspector General, and the Prince George’s County Police Department. Prosecutors credited the cooperation of multiple agencies and the courage of victims in bringing Cosby and her co-conspirators to justice.
Cosby’s sentence reflects the scale and sophistication of the scheme, which exploited the U.S. mail system and affected victims nationwide.
