A Delaware man was arrested outside a New Jersey elementary school Thursday after he was found with a loaded handgun and massive supplies of ammunition, prosecutors say.

The heavily armed man appears to have been targeting the school because of a relationship gone bad with a faculty member, according to a senior law enforcement official. 

Just before 4 p.m. Thursday, Westfield Police Department patrol officers and detectives responded to Tamaques Elementary School on a report from the New Castle County Police Department in Delaware that a man -- later identified as Thomas J. Wilkie, 46, of Bear, Delaware -- was en route to the school and possibly armed.

A senior law enforcement official briefed on the investigation says that the brother of the man arrested with ammo and a weapon at a NJ school was the person who alerted authorities that Wilkie was in a bad place mentally.

According to the official, Wilkie made entrance to the school searching for a woman he had been in a relationship with -- but he did not have a weapon on him at this point. When she wasn't there he allegedly returned to his car and called the woman who said she was at a tutoring appointment but would return to the school.

Wilkie then waited in his car and called his brother, the official said. Based on that call, the brother was concerned about Wilkie's state of mind and called the Delaware State Police and alerted them to the situation, according to the official.

The school was placed on lockdown as a precautionary measure, and to identify any potential threats. After-school programs were active at the time.

Arriving officers located Wilkie in the front seat of his vehicle, a 2019 Mitsubishi SUV, parked in the school’s parking lot, holding a .45-caliber handgun loaded with hollow-point bullets, prosecutors say.

It is illegal to possess hollow-point bullets in New Jersey unless you are a law enforcement, the law enforcement official briefed on the investigation said.

Wilkie had two additional loaded clips of ammunition, while 130 additional rounds of ammunition were located in the vehicle’s trunk, prosecutors say.

At this point law enforcement officials believe that Wilkie was out for the woman who he was formerly involved in a relationship and did not intend to kill others, but the amount of ammo is concerning they say, according to the person briefed on the case.

He is charged with second-degree unlawful possession of a weapon, fourth-degree possession of hollow-point bullets, and fourth-degree trespassing on school grounds, Union County Acting Prosecutor Jennifer Davenport announced Friday. The New Jersey Office of Homeland Security has been assisting with the investigation. 

Wilkie's first appearance and detention hearing scheduled to take place June 19.

Convictions on second-degree criminal charges are commonly punishable by 5 to 10 years in state prison.

Attorney information for Wilkie was not immediately known. 

A spokeswoman for the Westfield Public Schools said in a statement that the district is referring all inquiries to the Union County Prosecutor's Office "as this remains an active investigation."