LAWRENCE — A Lawrence General Hospital security guard has been arrested on charges of threatening to "wreak havoc" in the hospital by pulling a fire alarm and "shooting up the place."

Thomas Hyatt, 54, of 5 Mt. Vernon Terrace, who had worked at the hospital for four months, was arrested by police while on the job Tuesday night and charged with two counts of threatening to commit a crime.

The hospital fired Hyatt and ordered him to return his hospital issued clothing and gear.

Co-workers reported Hyatt made several threatening statements in recent months, including discussing how to bring a bomb into the facility. According to police, he also reportedly showed a co-worker a gun at a nearby movie theater and said, "If I could carry this at work, all the psychiatric patients would be dead."

On another occasion, during a fire drill, a co-worker said Hyatt was "explaining to me (in front of other co-workers) that he was thinking of what it would be like blowing up the hospital with an explosive device," one worker told police in a written statement.

"Not knowing how to react to such a statement, I jokingly stated 'with what, a grenade?,' and while showing me the length of nursing station 3, he said 'no, a grenade would only take out from here to there.' He said he would need something much larger," the co-worker wrote.

"That same day, he stated that his friend had brought in a handgun into the Emergency Center a few nights before and he went undetected. He began to say that the security at this hospital is minimal, and that anyone could enter the building. He then proceeded to tell me that he would enter the Russell lobby and 'take out' the people downstairs," the co-worker said.

Hyatt denied the charges, saying his comments were taken out of context. He said he was providing examples of ways security could be compromised in the building during a work evaluation. Hyatt told police he would never hurt anyone, and that he was merely raising questions about security issues at the hospital that concerned him.

Reached by telephone last night at home, Hyatt declined further comment.

Police searched his home after learning he had permits to carry guns in both Massachusetts and New Hampshire. More than a dozen handguns, an AR-15 assault rifle and numerous rounds of ammunition were found.

State records showed he had more than 30 weapons registered to him. Hyatt said the missing guns had been sold or are at a consignment store for sale.

Hyatt pleaded innocent during yesterday's arraignment. District Court Judge Stephen Ostrachand released Hyatt on his own recognizance and ordered him to stay away from the hospital and to comply with any restraining orders. The judge also imposed a bail warning, which if violated would result in Hyatt being jailed for up to 60 days without bail.

Hyatt cannot possess any firearms under the judge's orders. Besides the guns, police also seized his licenses to carry firearms in Massachusetts and New Hampshire.

The judge's conditions for Hyatt's pretrial release were recommended by Essex County Assistant District Attorney Jessica Strasnick, who is prosecuting the case.

Strasnick had also requested a $1,000 cash bail and that Hyatt undergo a psychological evaluation and treatment.

District Attorney spokesman Steve O'Connell said prosecutors didn't seek a dangerousness hearing for Hyatt because the charges he face are not covered under the law. A judge can declare a criminal defendant "dangerous" and impose pretrial jail confinement if evidence is produced which shows he or she poses a public threat.

Hyatt is due back in court March 19 for a pretrial hearing. North Andover Attorney Dolores Campbell is representing him. She could not be reached for comment last night.

Prior to his employment with the hospital, Hyatt worked in maintenance at Merrimack College, investigators said.