Abu Jindal, whose real name was killed in a Jammu and Kashmir encounter on Friday, Sep 4.
The officer said that Kasab, when shown Jindal's photographs said that he was not the same person who taught him Hindi.
"We have shown him (Kasab) Jindal's photographs provided by JK police. Kasab nodded in the negative when asked if the person in the photo was the same who taught them (he and his associates) Hindi," said the senior police official.
Initially in a special court Kasab had admitted that an Indian named Jindal taught him and the nine others to speak Hindi at an LeT training camp in Pakistan.
However, Mumbai's crime branch would still probe Jindal's involvement in the 26/11 attack.
"The verification is still on as we can not completely believe whatever Kasab says... earlier also he (Kasab) had tried to confuse and misguide the investigating officers. Many a times, he shifted blame on his co-accused despite his role in several acts during the Mumbai terror attacks," the officer said.