GREENSBURG — Plea negotiations are occurring in the case of a now-20-year-old charged with stabbing 20 fellow students and a security guard at Franklin Regional High School, attorneys said.

“I think there is a good chance it will be resolved before trial,” defense attorney Patrick Thomassey said on Wednesday.

Thomassey was referring to 21 counts each of attempted homicide and aggravated assault, plus a weapons charge, pending against Alex Hribal.

The then-16-year-old Hribal slashed his way through the hallways of the Murrysville high school before classes began on April 9, 2014, using two 8-inch kitchen knives he took from home.

Four students were critically injured and one required a liver transplant as a result of his injuries, but all the victims survived and have since recovered.

Thomassey has always acknowledged Hribal committed the crimes, but tried to have his client declared legally insane.

Defense and prosecution psychiatrists have testified Hribal purposely carried out the attack on the birthday of Eric Harris, one of two teens the doctors say Hribal “worshipped” for their attacks on Columbine High School near Denver on April 20, 1999.

But after extensive hearings on Hribal’s mental state last year, Westmoreland County Judge Christopher Feliciani in February refused to allow Hribal to plead guilty but mentally ill to the crimes.