Prayagraj, Sep 21 : A letter petition has been filed in the Allahabad High court seeking a CBI probe into the mysterious death of Akhil Bhartiya Akhara Parishad (ABAP) chief Mahant Narendra Giri. The petition has been filed by advocate Sunil Chaudhary. The petitioner said that the circumstances in which the Mahant was found dead on Monday evening were highly suspicious and mysterious. Some of the members of the Akhara have raised doubts over the five-page suicide letter, purportedly written by Mahant Narendra Giri. Mahant Anand Giri, one of his disciples, who is a key suspect and has been taken into custody from Haridwar, also said that the Mahant had never written anything beyond a sentence or two and it was highly improbable that he would write such a lengthy suicide letter. What adds to the element of mystery is that the suicide letter also reads like a will since the Mahant has apparently designated work and responsibilities for his disciples. Saints are also saying that Narendra Giri could never have committed suicide. The police has detained three persons so far -- Anand Giri, Adya Tiwari, the priest of Hanuman temple, and his son Sandeep Tiwari -- for questioning. Their names were mentioned in the suicide note. The petition also refers to the statement given by Mahant Anand Giri, one of the suspects, which questions the role of some police officers of Prayagraj. Former BJP MP Vinay Katiyar has also sought a CBI inquiry into the death of the Mahant, said: 'This is the only way to ensure an impartial probe." /IANS