The case related to the suicide of a five-member family of a temple priest following the alleged sexual abuse of a teenage girl member of the family.
Judge P S T Moosath ordered the CBI to probe the alleged role of politicians while allowing a petition filed by Unnikrishnan Namboothri, paternal uncle of the 15-year old victim.
The court rejected the CBI report that the girl had been sexually abused by her own father before her death.
Bodies of the girl, her father Narayanan Namboothiri (40), mother and eight-year old sister and six-year old brother were found in their house at Kaviyoor in Pathanamthitta district on September 28, 2004.
Narayanan Namboothiri was a priest in a local temple.