A report in The Kathmandu Post says Sobhraj started his latest antics after he was kept in solitary confinement three weeks ago for conning the Lebanese accused of overstaying his visa.
Quoting a prison official, the report says Sobhraj had duped the fellow prison mate of the sum by assuring to get him out on bail with help of his mother-in-law who is also a lawyer.
A prison guard says that after his solitary confinement, Sobhray stopped using the toilet and started littering his cell.
The report says Sobhraj might be indulging doing this to vent anger at prison officials and ensure they get their hands dirty when they check his cell.
The stench from his body waste is also affecting other prisoners.
"I don't have any grudges to share with you," Sobhraj told the daily.
The Bikini Killer who cooks his own food and has a television and water heater inside his cell, keeps himself busy reading and writing and watching movies and news.
Sobhraj was arrested in 2003 and is serving life sentence for murdering American tourist Connie Joe Bronzich in 1975.