A Butler man allegedly was in a “drug-induced rage” when he attacked a new roommate with a baseball bat at their apartment, according to testimony at a preliminary hearing Monday.

The Nov. 17 attack at the West New Castle Street apartment was unprovoked, the 21-year-old victim said. The Massachusetts man was left in need of hospital treatment for numerous injuries, including a bleeding gash to the back of his head.

District Judge William Fullerton ordered 31-year-old Stephen M. Netz held for trial on a felony charge of aggravated assault. Netz remains in the Butler County Prison in lieu of $25,000 bond.

Christopher Mason, 21, of Boston, testified that he was “desperate” for a place to stay and agreed to pay Netz $400 to rent a room at the defendant's apartment Nov. 12. That was the first time he met Netz.

Prosecutor Terri Schultz, a county assistant district attorney, asked him what happened five days after that initial meeting.

“I was on his air mattress in his room,” Mason said. “We were hanging out. We didn't have no negative tension at all.”

He said he was on his cellphone. It was around 8:30 p.m.

“And out of nowhere,” Mason recounted, “(Netz) just decided to bring out a baseball bat and start swinging and told me to get the 'F' out of his apartment.”

He told Schultz that he was first struck in the left calf and then the right kneecap. He was hit on the hand, both forearms, his back, the back of his head and his right bicep.

“My immediate response, because I'm new to the area and I don't want any problems at all, I just was in flight mode,” Mason said. “I never laid hands (on Netz).”

He went out the door and into the hallway.

“Mr. Netz then hit me,” the victim said, “and I fell down a flight of stairs, and from there he kept whacking me.”

Mason said he was able to get out of the building and walk two or three blocks before he called 911.

Patrolman Jacob May found the Mason on West North Street.

“I observed that he was walking with a limp and bleeding from a gash in the back of his head,” May testified.

When the officer noted that Mason identified the defendant as his attacker and the bat as the weapon, there came a response from the defense table — but it was not from Netz's attorney, public attorney Maura Palumbi.

“Objection,” the defendant cried out, interrupting May's testimony.

Fullerton quickly chided Netz.

“Sir, you have counsel,” Fullerton said. “Counsel will lodge any objections.”

On cross-examination, Palumbi asked May if Netz told police what prompted the attack.

“The victim stated that, his exact words was that Mr. Netz was in a 'drug-induced rage,'” the officer testified, “and he didn't really have much more explanation other than that.”

Palumbi asked Mason if he saw her client consume drugs.

“I seen him use crack cocaine on a few occasions,” he replied.

Mason denied using drugs with Netz. The victim said the only drug he has used was marijuana. He also denied being under the influence at the time of the alleged assault.

Palumbi asked Mason if Netz was attempting to evict him from the apartment.

“When someone randomly comes at you with a baseball bat from far out of left field,” he said, “that pretty much sends the message to get out. Yes?”

Police suspected the defendant was impaired on drugs when they got to his apartment that night.

“He was not acting normally,” May said of Netz. “He did appear to be under the influence of some narcotic.”

The officer told Palumbi that her client allowed police to come into the apartment and take the bat.

But on continued cross-examination, May admitted that Netz did not sign any consent form to search the apartment, nor was he advised that he had the right to refuse the search.

Mason was taken by ambulance to Butler Memorial Hospital soon after police found him. He was treated for injuries and diagnosed with contusions, a cut to the back of the head and a hematoma.