When Shantell Shaw showed up for her first day as a Memphis City Schools teacher in 2008 at Trezevant High School, she was assigned a mentor.

Her mentor was Clarence Mumford Sr., a guidance counselor at the Frayser school. And Mumford later asked Shaw to take a PRAXIS teachers examination in biology for a teacher who had already failed the test 11 times, according to Shaw.

Shaw pleaded guilty in a criminal information Thursday, Oct. 4, to a federal charge of conspiracy to defraud the government. An information is a legal process in which a defendant is charged and pleads guilty in the same hearing.

Carlos Shaw, another Memphis City Schools teacher and unrelated to Shantell Shaw, pleaded guilty to the same charge Thursday afternoon in a separate information before U.S. District Court Judge John Fowlkes.

Their guilty pleas bring the total to four in the ongoing federal investigation of the teacher test cheating scandal in which Mumford was the alleged ringleader. All four of those who pleaded guilty in separate cases have admitted they took PRAXIS exams in the three-state Mid-South area in the names of other teachers and would-be teachers. Teachers must pass the exams in order to teach or continue to teach in local school systems in West Tennessee, North Mississippi and Eastern Arkansas.

Mumford and 10 others are charged in a separate indictment.

U.S. Attorney Ed Stanton said Thursday the new cases are “another step in the ongoing effort to uncover anyone involved in this conspiracy and ensure that they are held accountable for their unethical and illegal acts.

“These prosecutions are critical to protecting the integrity of our education system, preserving the reputation of honest, hard-working educators and guaranteeing our students get the quality education they deserve,” he added.

Shantell Shaw said her first reaction when Mumford approached her about taking the biology certification exam was to refuse. She relented in March 2009 after she met the teacher and was paid $1,000. Shaw took 12 to 15 PRAXIS exams in the names of others and made approximately $8,000 as a result, according to the information.

Carlos Shaw said Mumford first approached him 10 years ago about taking teacher exams in the names of others. At the time, he and Mumford taught summer school together. Carlos Shaw also said he initially refused but that Mumford repeatedly approached him about the scheme and he eventually agreed.

Carlos Shaw was once assistant principal at the Memphis Academy of Science and Engineering and had taught at Carver High School and Booker T. Washington High School.