WASHINGTON (AFP) – A US 19-year-old has been indicted on hate-crime charges for using a webcam to capture a gay encounter involving his roommate, who later committed suicide.

Dharun Ravi was originally charged in September 2010, after his Rutgers University freshman roommate Tyler Clementi, 18, killed himself by jumping into the Hudson River.

But a newly released indictment by a grand jury in the northeast state of New Jersey adds charges that could result in a 10-year prison sentence.

The 15-count indictment includes charges of bias, invasion of privacy with the purpose to intimidate because of sexual orientation, tampering with evidence and witness tampering.

"Under state law, bias is charged a degree higher than the underlying crime, in this case, invasion of privacy," county prosecutors said in a statement.

"The defendant has also been charged with two counts of second-degree bias and two counts of third-degree bias. A second-degree offense carries a prison exposure of five to 10 years," they added.

Grand juries in the United States work behind closed doors and issue indictments if probable cause exists. Criminal trial juries must find guilt beyond a reasonable doubt to convict a defendant.

The case had been the latest in a string of suicides by gay and lesbian youth and sparked a campaign against bullying.