A Texas man woke up Tuesday morning to find an anti-gay slur and phallic symbol spray-painted on his front door.

Eric Arthur of McKinney, about 30 miles north of Dallas, says he's never had a problem with homophobia in the five years he's lived the area.

But a neighbor alerted him that morning that someone had sprayed "fag" on his door.

"I opened the door and immediately feel my stomach in my chest," Arthur, who came out when he was 18, told WFAA ABC 8. "[I'm] vulnerable, scared, confused… I think every emotion I could possibly feel at the time it was happening."

His concern was how targeted the attack was: "If they knew me well enough, why would they do this to me?"

Neighbor Byron Bounds, whose son is gay, said "[it] is just totally uncalled for… for something so idiotic to take place."

Police have begun an investigation—and while a department spokesperson said it's believed to be an isolated incident, the case has been assigned to a detective.

Still shaken, Arthur bought a security system on Wednesday. "If they feel it's okay to do that to your property, what's keeping them from taking it a step further?" he asked.

In September 2014, Money magazine ranked McKinney the "Best Places to Live in the United States."