Alwin Chen, 18, was charged February 15 with bringing this loaded gun to Clarksburg High School in Montgomery County, Maryland. (N/A/Montgomery County Police )

Police in Maryland found an AR-15 styled rifle, a shotgun, two handguns, ammunition and a tactical vest in the home of an 18-year-old honor roll student who police say last week brought a loaded 9mm handgun to school, authorities said Tuesday.

Officers also discovered that the suspect — Alwin Chen, a student at Clarksburg High School in Montgomery County — had previously brought the same handgun to school and had compiled a “list of grievances against students in the school,” Montgomery Assistant State’s Attorney Frank Lazzaro said.

He termed the list “possibly a motive for why he was going to use the gun.”

The precise motive and overall thinking of Chen remained unclear Tuesday. Detectives and prosecutors continue to probe the case.

Chen is charged with possession of a handgun, possession of a firearm by a person under 21 and possession of a firearm on school property.

Given the weapons at his Germantown home, the accusation that he has brought a gun to school at least twice, and the alleged grievance list, Montgomery District Judge John C. Moffett said Chen “presents a serious danger to the community.”

He ordered Chen to be held in jail without an opportunity to post bond.

For his part, Chen allegedly gave police two different explanations on Thursday after a school resource officer found a loaded Glock 9mm in his book bag. The discovery came a day after a shooting at a Florida high school that killed 17 in an attack authorities say was carried out by a former student.

First, Chen said, he was going to do target practice after school, prosecutors said in Chen’s initial court appearance.

He “then told the police he had brought the gun to school for possible protection because students at the school had been harassing him and bullying him,” Lazzaro said.

“In this day and age,” added Montgomery’s top prosecutor, John McCarthy, “there’s got to be zero tolerance on the acceptability of bringing a loaded handgun onto school property.”

The purchase history of the weapons and gear was not detailed in court.

As for Chen allegedly bringing the gun to school earlier, detectives learned about that incident after Thursday’s arrest, said Capt. Paul Starks, a Montgomery police spokesman. Derek Turner, a spokesman for the school system, said the school also was not aware, before Thursday, about Chen allegedly bringing the gun to school on a previous date.

Detectives are working to confirm ownership of guns seized from Chen’s home. They said there was no indication the weapons were owned by anyone other than the home’s occupants. Detectives also seized and examined a journal kept by Chen.

“There is no wording regarding any threat nor any expression of wanting to cause harm to anyone at the school,” police said Tuesday in a statement, describing the journal’s content.

David Felsen, an attorney for Chen, stressed in court that the weapons were not found in his client’s bedroom, and noted his accomplishments before the allegations.

“They were found in someone else’s room,” Felsen said. “Someone who is, we believe, authorized to have all these things.”

Felsen said Chen has received two college scholarship offers — from schools in Maryland and Florida — is on the honor roll, and “has never been in any trouble.”

He also said his client does not appear to suffer from mental illness.

“There is no hint of any ­mental-health issue at all,” he said in court.

Chen’s parents were in court Tuesday.

In ruling that Chen should be held with no bond, the judge spoke about them and their son. “It’s a difficult situation,” Moffett said. “Individuals with access to weapons that pose a serious, imminent threat or danger to the community are not tagged with a neon sign or a warning sign.”

“Looking at his parents,” Moffett said, “I don’t see any neon sign or flag on them that would make me think they have these types of weapons” in their home.

Felsen did not discuss why his client may have brought a loaded gun to school. But he suggested Chen didn’t intend to hurt anyone.

“This is a young man who has desires of helping people, in terms of being a police officer or being in the military,” Felsen said.

Felsen said Chen lives in a home with his parents and at least one other relative.

“He is very polite, well-mannered,” Felsen said.

Chen’s parents immigrated from China and run a business in the exporting field. He was born in the United States.

“They are hard-working. They have a business. They work together. They’re very quiet, gentle people,” Felsen said. “They are very involved parents. They are worried for their son’s safety in the jail, as any parent would be.”

Chen’s parents are not worried he was about to hurt anyone, Felsen said. “They are confident he did not present a danger to anyone,” Felsen said.

Felsen said he could not comment on reports of Chen previously bringing a gun to school or any kind of “grievance list,” because he heard those allegations for the first time in court Tuesday. Felsen said he did not know how the school resource officer got the alleged tip about the Glock Model 19 9mm handgun.