Carbondale (US), Jun 17 (IANS): After a four-year crusade by an Indian-American mother seeking justice for her murdered son, the assailant has finally been convicted.

A jury on Thursday found Gaege Bethune guilty of Pravin Varughese's murder in Carbondale in 2014, according to media reports.

After the verdict, Pravin's mother Lovely Varughese told the Chicago Tribune: "Pravin's day finally came. He can rest in peace now."

After authorities had dismissed Pravin's death as an accident, his mother waged the relentless crusade mobilising politicians, media and the public.

Under pressure, authorities ordered a fresh investigation and appointed a special prosecutor.

Carbondale Police Chief Jody O'Guinn was also dismissed.

Bethune now faces a sentence of 20 years to 60 years.

The 19-year-old Pravin's body was found in a forested area in a frozen condition in February 2014, four days after the Southern Illinois University student went missing.

The local coroner declared his death an accident caused by exposure to extreme cold.

But his family commissioned an independent post-mortem which found that he had died from a severe blow to his head and had other injuries.

Lovely Varughese held several news conferences and addressed vigils to draw attention to the finding.

Volunteers from Archangels of Justice, a retired law enforcement officials' organisation, researched the case and wrote a report that pointed to Bethune.

The family's campaign rallied the support of community, with over 500 people attending his death anniversary observance.

Congressman Danny K. Davis took up the issue with the Justice Department and Congresswoman Jan Schakowsky, then-Congressman Bob Dold and former Illinois Lieutenant Governor Sheila Simon joined the demand for a proper investigation.

Lovely Varughese also filed a case against Carbondale, its police department and O'Guin alleging negligence and seeking $5 million in damages.

The local prosecutor, Michael Carr, who initially took up the case removed himself from it after failing to get a grand jury to charge Bethune.

Special Prosecutor David Robinson, who was appointed to take it up, tried the case and got Bethune convicted.

The charge against Bethune said that even though Pravin might have frozen to death it "was a natural and foreseeable consequence of that independent felonious conduct" of the aggravated assault by Bethune.

The prosecution said that Bethune had given Pravin a lift and allegedly went looking for cocaine, according to the St. Louis Post-Dispatch.

A dispute ensued over money when Pravin made him stop the vehicle and got out.

Bethune then attacked him and took the money, leaving Pravin injured and in early stages of hypothermia, the newspaper said quoting the special prosecutor.

A state police trooper who passed by questioned Bethune but let him off after he told him that he had picked up a hitch-hiker who tried to rob him and that he had chased him into the woods.