PARIS – A Rumford man who was first charged with elevated aggravated assault after police said he broke into his ex-girlfriend’s home and stabbed her new boyfriend in the neck now faces an attempted murder charge.

The new charge was added to the case against Dwight Knox, 38, of Franklin Street in Rumford during his initial appearance in court May 15, Assistant District Attorney Richard Beauschene said.

“We reviewed the case and felt in addition to the aggravated assault charge there was probable cause for the additional charge,” Beauschene said Monday.

The felony charges against Knox would go to an Oxford County grand jury for review next month, Beauschene said.

Both charges are Class A felonies, and, if convicted, Knox could face up to a 30-year prison sentence for each charge. Knox is being held at Oxford County Jail on $25,000 cash bail, an increase over the $500 bail set on the original elevated aggravated assault charge.

According to state records in Maine and Florida, Knox has an extensive conviction record, including five convictions for assault in Maine dating back to 1997. He was also convicted on a criminal threatening charge and two charges of theft by unauthorized taking.

Knox’s criminal record in Florida is also extensive and shows he spent time in the Polk County Jail after being convicted for assaulting law enforcement officers and for being a felon in possession of a firearm. His other Florida convictions include indecent exposure, burglary and shoplifting.

Another charge in his Florida criminal record shows Knox was charged with homicide and attempted homicide in 1990 but was not convicted.

Rumford police Detective Sgt. Daniel Garbarini said police served a search warrant at Knox’s residence Monday, and evidence was recovered that would be forwarded to the Maine State Police Crime Lab in Augusta for examination.

Garbarini said he couldn’t disclose what evidence was seized.