PHOENIX -- There's a candle burning in Michael Arvallo's memory in his mother’s home in Phoenix.
There's also a burning desire for answers inside the house.
“I hope to God somebody's out there and helps us,” said Margaret Arvallo.
One year ago Arvallo’s 49-year-old son was shot and killed on I-10 near 51st Avenue.
Police found him with a bullet in the head.
Investigators also found his black Chevy pickup truck mangled in the center median.
Arvallo’s girlfriend thought by now the shooter would’ve been caught.
“It's hard not knowing who did this and why. He wasn't a violent person,” said Katherine Jaramillo.
The father of four was on his way home from a charity bowling event.
Arvallo was found dead just four miles away from home.
His older brother, Manuel, invited him out that night and remembers how much his friends liked Arvallo.
“He introduced himself to everybody. They all knew who he was before I got there. Everybody thought he was an awesome person and said ‘Wow you have a great brother,’” said Manuel.
An older brother is now ridden with guilt.
But the family knows their focus must be on justice.
“There's got to be just one person who saw something. Maybe it's something they think is nothing. But the detectives maybe they can go by that,” said Arvallo.
A spokesperson with the Phoenix Police Department was unavailable to comment.