Updated

District of Columbia schools officials say they've found cheating at 11 schools during the last school year.

The district's Office of the State Superintendent released results Friday from its annual audit of standardized testing in the city. It says "critical violations" of testing integrity were found at seven public schools and four charter schools. Test results from those schools will be thrown out.

The audit was released on the same day it was revealed that city school officials knew in early 2009 about possible widespread cheating. An internal memo shows that an analyst found 191 teachers at 70 schools may have erased their students' wrong answers and filled in the right ones.

Two investigations of the erasures found only isolated cheating. One teacher was fired.