NEWARK -- After hanging out at a friend's home and playing video games in June 2014, Brendan Tevlin texted his mother, Allison, that he was on his way home.



But a few minutes later, Tevlin was gunned down in his car at a traffic light in West Orange for no other reason than he was an American, his mother said.



"It's a parent's worst nightmare," she said.



Allison Tevlin offered that explanation for her son's shooting death on Tuesday after watching the alleged killer, Ali Muhammad Brown, arraigned on terrorism, murder and related charges.



Brown, 30, of Seattle, pleaded not guilty to the charges during the brief court appearance. Brown has told investigators he killed Tevlin as an act of "vengeance" for innocent lives lost in Iraq, Afghanistan, Syria and Iran.



Standing outside the courthouse after Tuesday's hearing, Allison Tevlin praised Essex County prosecutors for bringing terrorism charges against Brown.

"We are grateful that the prosecutor sought and obtained an indictment under New Jersey's anti-terrorism statute," Allison Tevlin told reporters while standing beside her husband, Michael, and other family members.



"It is our belief that Brendan was senselessly executed for no reason other than he was an American and that this outrageous fact will be proven at trial," she added.

Brendan Tevlin, 19, shown in his 2013 Seton Hall Preparatory School yearbook photo. A year after his murder, community members say there are daily reminders of Tevlin in and around his family's hometown. (Seton Hall Preparatory School Yearbook)

Allison Tevlin also thanked both the prosecutor's office for its dedication to the case and "all the law enforcement authorities who have worked so tirelessly to seek justice for our son, Brendan, over the past year."



"Finally, we wish to extend our thanks to the countless people from literally all over the world who's extended their love and support to our family," she said.



"We will continue to honor Brendan by focusing our efforts on how he lived and not how he died and by staying true to his motto of 'Good Vibes and Easy Living.'"

Michael Tevlin said he and his wife were holding up the "best we can." "It's going to be a long process," he said.

Asked about her reaction upon seeing Brown in the courtroom on Tuesday, Allison Tevlin said: "He doesn't deserve a reaction."

Authorities have said Brown killed Tevlin, 19, on June 25, 2014 when he and at least three other men attempted to rob Tevlin at a traffic light at Walker Road and Northfield Avenue in West Orange.



While the other men fled the scene, Brown moved Tevlin's body into the passenger seat of Tevlin's Jeep Liberty and drove it to a nearby apartment building, where he abandoned it, authorities said. A Livingston resident, Tevlin had just returned home from his freshman year at college.



Brown was indicted last month on terrorism, murder, robbery, carjacking and related offenses. The case marks the first time that the state's anti-terrorism statute has been used in a murder case.



The charges against Brown's co-defendants, Eric Williams and Jeremy Villagran, have been dropped.



Brown's attorney, Albert Kapin, declined to comment after Tuesday's hearing.

MORE: Terrorism charge could ensure life sentence for alleged Brendan Tevlin killer, attorney says

Tevlin's killing marks one of a series of crimes allegedly committed by Brown after coming to New Jersey from Washington State, where he also is charged with killing three men.



Four days after the fatal shooting, Brown allegedly robbed a man on June 29, 2014 at a coffee shop in Point Pleasant Beach.



In that case, Brown is accused of approaching the victim outside Green Planet Coffee, showing him a gun in his waistband and demanding that the man come with him, authorities said.



After the victim ran into the business to have 911 called, Brown followed him inside, forced the man to the ground and pointed the gun at his head, demanding his car keys and wallet, authorities said.



The man turned over the items and Brown left the coffee shop, authorities said. Brown tried to steal the man's vehicle, but he was unable to drive the car's manual transmission and then fled the scene, authorities said.



Brown was indicted on July 23 in that case on robbery, aggravated assault, carjacking and related offenses.



About two weeks after Tevlin's killing, Brown is accused of robbing a man on July 10, 2014 in the parking lot of an apartment building at 200 Mount Pleasant Avenue in West Orange. Authorities have said Brown approached the victim, robbed him of his wallet and fled the scene.



Brown was arrested on July 18, 2014 when police found him living in a makeshift campsite in West Orange.



Brown was indicted in January on robbery and weapons offenses in connection with the West Orange robbery. He is scheduled to go on trial in that case in October.

Bill Wichert may be reached at bwichert@njadvancemedia.com. Follow him on Twitter @BillWichertNJ. Find NJ.com on Facebook.