The CPI-M on Monday said the acquittal of all the 16 accused in the massacre of 42 Muslims at Hashimpura in Uttar Pradesh in 1987 should be pursued in the higher court.
"The acquittal by a Delhi court of all the 16 accused in the Hashimpura (Meerut) massacre has angered those who had wanted to see that justice is done in this police atrocity," it said in a statement.
"The acquittal due to insufficient evidence highlights the callous manner in which the prosecution of those guilty for communal killings are being conducted," the Communist Party of India-Marxist said.
The party demanded that the verdict be appealed and the case "strongly pursued" in the higher court.
Provincial Armed Constabulary (PAC) personnel rounded up the 42 Muslims from Hashimpura locality in Meerut on May 22, 1987 during Hindu-Muslim riots, shot them dead and dumped their bodies in water canals.
This triggered a long legal battle in courts. On Saturday, a lower court in Delhi acquitted all the surviving accused for lack of evidence.