Besides Bhattarai, the apex court also summoned Attorney General Mukti Narayan Pradhan in connection with the case.
The court has sought a written explanation from Bhattarai, who is also the law minister, and Pradhan within a week.
A single bench of Justice Sushila Karki ordered the duo yesterday to clarify whether their move to intervene in the ongoing investigation in the killing of journalist Dekendra Raj Thapa could be regarded as contempt of court.
"Both the prime minister and attorney general are directed to clear the air in writing within seven days," said court spokesperson Shrikant Paudel.
The bench was responding to a contempt of court case jointly filed by the lawyers' and journalists' associations on January 13.
Thapa, a reporter of state-run Radio Nepal, was abducted by alleged Maoist rebels from Dailekh district in 2004 during the civil war. The Maoists allegedly tortured him in captivity for about a month before burying him alive. His body was found in a jungle near Dwari village four years later in 2008.
The police last week had arrested five Maoist cadres in connection to the abduction and murder.
Bhattarai, who himself is a Maoist leader, had expressed dissatisfaction over the arrest of the Maoist cadres in the case, saying resurrection of civil war era cases was against the spirit of the peace accord.
Earlier on January 15, the Apex Court had issued a stay order against the Attorney General's letter to Dailekh district attorney and police to halt investigation into the murder.
Under the Nepalese law, those held guilty on the contempt of court charge would be liable to face a one-year jail or a fine of Rs 10,000 or both, Kantipur Online reported.
Kathmandu: Nepal Prime Minister Baburam Bhattarai has been summoned by the Supreme Court on contempt of court charges, over his alleged attempt to intervene in an ongoing case related to the 2004 killing of a journalist in which Maoist cadres have been arrested.
First Published: Saturday, January 19, 2013, 16:14