As the Riverhead community mourns the death of popular student-athlete John Anderson, his distraught father is trying to understand why he took his own life.

Anderson, a captain of the varsity football team at Riverhead High School, died Sunday of a self-inflicted gunshot wound, Dennis Anderson said. He was 18.

“I don’t understand why at all,” Dennis Anderson said. “It doesn’t make sense. He’s never been happier. He was looking forward to so many things in his life.

“He’s loved by everyone and had so many friends. He served the church. He just got a job at Lowe’s. He was going to graduate and go play football at Cortland. He was a great son.”

Riverhead police said they received a call at 3:12 p.m. Sunday, and Anderson’s body was discovered at Reeves Beach in Riverhead. The incident is still being investigated, but police said there was no evidence of foul play.

Known as “Big Bear 63’’ — 63 was his uniform number — Anderson was a role model and mentor for the younger players, according to Riverhead football coach Leif Shay. The 6-2, 265-pound senior commanded the respect of his peers and opponents alike.

“He was a very respectful kid,” Shay said. “He carried himself with a lot of dignity. Big John was loved by everyone.”

advertisement | advertise on newsday

Shay said the high school administration has made counselors available to students. A number of grief-stricken students did not attend school earlier in the week, he said.

“He was the designated driver for all his friends,” Dennis Anderson said. “Whether it was a ride to and from football practice or a ride home from a party, he was there for everyone. I used to give him a hard time about all the gas he used and he would say, ‘Dad, these guys need a ride, it’s so important.’ ”

Anderson said his wife of 27 years, Carmel, and daughter Maria, 19, are heartbroken and searching for answers. He said his anguish may never subside and that he may never know why his son took his own life. But he said he wants to know how John acquired the weapon.

The Riverhead Town Board held a moment of silence Tuesday before its regular meeting, when Bishop Emil Wcela, of St. John the Evangelist Roman Catholic Church in Riverhead, asked the town to pray for the Anderson family.

“John came to church with us every Saturday night or Sunday morning at St. John the Baptist in Wading River,” Carmel Anderson said. “He never gave us a hard time because he loved his faith. He helped with the liturgy of the Word for children once every few weeks. He would stand up and the pastor would give him the book and all the children would follow him out of the church and he would do the readings in words the children would understand.”

Riverhead Town Councilman Tim Hubbard said he coached Anderson at age 7 in the Police Athletic League. Hubbard said he was always “hard-working, nice and respectful. He was everything you would want in your own kid. It’s very hard. My heart goes out to his family.”

More than 200 attended a vigil in Anderson’s memory Monday night. Candles were arranged in a large “63’’ and friends spoke glowingly of him.

“He was an amazing little brother,” Maria Anderson said. “We’re only 17 months apart and we became so close in high school. He could joke around with me and confide in me, and I loved that.”

Viewing is Thursday from 2-4 p.m. and 7-9 p.m. at the Alexander Tuthill Funeral Home in Wading River. A funeral Mass will be Friday at 10 a.m. at St. John the Baptist. Interment will be at Calverton National Cemetery.

With Jean-Paul Salamanca