LITTLE EGG HARBOR TOWNSHIP, NJ (CBS) – Authorities in New Jersey say a gunman shot and killed his brother and a Good Samaritan before being taking his own life Monday.

The deadly incident began at about 10 a.m. near the Tall Timbers condos on Westchester Drive in Little Egg Harbor Township, Ocean County.

According to investigators, 45-year-old Craig Mueller fired several shots with a semi-automatic military rifle from a second story window at the complex.

Police say one of the fatalities was the gunman’s brother, 52-year-old Bryan Mueller. The second victim was 21-year-old Kara Ellis. Police say Ellis was trying to help Bryan Mueller when she was fatally shot.

“Cara was outside and walking and saw what happened and tried to render assistance to Bryan and she was caught in the crossfire,” said Ocean County Prosecutor Marlene Lynch Ford.

At about 2 p.m., a SWAT team entered the residence that the brothers shared and found Craig Mueller dead with a self-inflicted gunshot wound.

It was not immediately known what sparked the deadly shooting.

“At this point, it’s a mystery,” Ford said, referring to a possible motive for the deadly incident.

Schools in the area were placed on lockdown until about 3:15 p.m.

Meanwhile, in an unrelated incident, authorities in New Jersey say the Cape May County SWAT team shot and killed a man who was coming at them with weapons on Sunday night.

The New Jersey Attorney General’s Office says it is investigating that shooting, in which 37-year-old Douglas Wnek of Middle Township, near Wildwood, died.

According to a spokesman for the attorney general, Wnek’s wife, Amber, called police to report her husband was alone inside their home, armed and suicidal. Police, including the county SWAT team and hostage negotiators, responded.

The spokesman says they were trying to negotiate a peaceful surrender when Wnek made several threatening statements and left the house carrying two rifles and a shotgun. He says SWAT officers opened fire when Wnek failed to respond to commands from police, killing him.

Police declined to provide any other details. The phone to the Wneks’ home has been disconnected.

Reported by Pat Loeb, KYW Newsradio and Cydney Long, CBS 3