Pamela Coss was sleeping when the phone rang in the wee hours of Jan. 8, 2012. Her only child was at a party with his cousin.

“I still wake up in the middle of the night because that’s when I got the call he was shot,” said Coss.

Fabian Cota was shot in the head. The 19-year-old was in the backyard when two people drove by the party and opened fire.

“I relive it every day because I miss him,” said Coss.

Investigators have questioned witnesses but so far no one has been arrested and charged. Coss says Phoenix police have identified a potential suspect but don’t have enough evidence to charge him.

“I’ve gone to his home and given him (reward flyers)," Coss said. "I don’t’ want him to forget."

A room in the family house is filled with pictures and mementos of Fabian. The garage is filled with everything he owned.

“I just can’t get rid of it,” said Coss.

There are boxes and boxes packed with his favorites video games and comic books.

Still grieving, Coss says she has just recently been able to visit her son’s gravesite and spend more than a few minutes there.

“I used to go and clean it up and then leave,” said Coss. “Now I can go there and talk to him.”

The case, according to Coss, has gone cold despite a potential suspect identified.

“An arrest is not going to give a family closure. They are always going to feel a loss, but we want to give them the gift of an arrest,” said Silent Witness Spokesperson Jamie Rothschild.

Pamela Coss has several reward flyers already printed and ready to pass out or put up. Occasionally she will go to the neighborhood where the shooting happened and hand them out, hoping someone will one day come forward.

“No one will talk, no one will talk,” said Coss.

Fighting back tears she shared memories of her son, while making sure everyone knows she will never stop trying to catch the person who killed her son.

If you have any information about this case, call Silent Witness at 480-948-6377 (WITNESS).