District Sessions Judge Rama Jain rejected the bail plea of Rakesh, wife of victim Gajender Singh, along with her son Ashok, who was also arrested for the crime.
According to prosecution sources, Singh was strangled to death by his wife and son over a property dispute at Almaspur village in the district on February 17.
His body was later found in a box at Muzaffarnagar railway station by the Railway police, the sources said.
The two accused kept the box in the train posing as passengers, they said.