The man accused of fatally shooting his mother in a New Hampshire hospital Tuesday pleaded not guilty to first-degree murder. Travis Frink, 48, of Warwick, Rhode Island, was ordered held without bail.

An emotionless Travis Frink walked into court in handcuffs and a jail jumpsuit.

Prosecutors say he shot his mother, Pamela Ferriere, 70, of Groton, New Hampshire, while she was in the ICU at Dartmouth-Hitchcock Medical Center for a brain aneurism.

"I cannot begin to express the amount of trauma that both have endured from witnessing yesterday's events," said New Hampshire Assoc. Attorney General Jane Young.

A nurse told police she saw Frink pull out a handgun and then heard two shots followed by screams. Frink's stepfather, who was also in the hospital room, told police the suspect asked for a moment alone with his mother, and then watched his stepson point a gun and fire shots.

"If there's anybody out there that has information about Mr. Frink in the days leading up to yesterday, or if anybody saw him yesterday at the hospital, that you contact the lead detective," Young said.

Frink allegedly told police he intended to kill his mother, and drove up from his Warwick, Rhode Island, home earlier in the day to do it.

"At a time of an active shooter in the hospital -- in the event -- we did what we were trained to do," said Dr. Edward Merrens, DHMC's Chief Clinical Officer.

Dozens of police officers responded, detaining Frink as he tried to leave. The hospital says no other patients or staff members were hurt, and their internal response is under review. "We've trained for this, and people were ready. Ready for something that you should never be ready for," Merrens said.

The affidavit says Robert Ferriere told investigators he had no idea why Frink would want to kill his mother. Pamela Ferriere was supposed to go home Friday. Wednesday, the attorney general asked the media to respect Robert Ferriere's privacy.

The Associated Press reports Frink's wife and 3-year-old son were found dead in 2013 inside a running car that reeked of alcohol and vomit.

Frink's LinkedIn page includes a long list of experience in computer systems administration and technical support jobs in Rhode Island, Connecticut, New York and Massachusetts. Messages left with the company listed as his current employer weren't immediately returned. Several of Frink's neighbors in Warwick said he mostly kept to himself.

The president and CEO of the hospital, Dr. Joanne Conroy, issued a statement Tuesday night thanking staff members for their response to the shooting.

"This is what we have trained to do, and all of you did exactly what you have been instructed," Conroy said. "We will work closely with local and state law enforcement to learn how this happened so that we can ensure this will never happen to one of our patients again."

This marks the second deadly shooting inside a New Hampshire hospital's ICU in three years. Back in 2014, a man killed his wife and himself at the hospital in Dover.

Anyone who saw Frink before or after the shooting at the hospital is asked to call New Hampshire State Police at 603-419-8097.