SAN DIEGO -- A family's quest to bring justice to their daughter was stalled by a deadlocked jury, 10News reported.

A mistrial was declared Monday in the case against Anthony Miller, who is charged in the slayings of Heather Mattia and Firas Eiso.

The execution-style killings were caught on a surveillance camera, and Heather Mattia's father said the case should have been open and shut.

Miller is one of two people charged in the 2006 double murder, and his co-defendant Jean Pierre Rices has already admitted to the killings.

However, Miller maintained he was forced by Rices to accompany him on the night of the slayings.

Eiso and Mattia were clerks at an El Cajon liquor store when two men held them up at gunpoint, had them lay on the ground and executed them.

Omar Serdah found the bodies of Mattia and Eiso when he went to the liquor store to buy a drink.

"For me, it was a nightmare. I couldn't go to sleep that night," said Serdah.

Serdah said he was surprised that Miller is getting a new trial.

"If they have all the proof -- they have the surveillance cameras -- and he did it, I don't know why they do it again," said Serdah.

On the heels of a hung jury and a new trial for Miller, Nabil Mattia showed 10News how he remembers his daughter.

"Right now it's been three years, 3 months and 22 days. I've been counting day by day," said Mattia.

As he counts the days since he last saw his daughter, a jury's 11-to-1 guilty vote forced Judge Lantz Lewis to declare a mistrial.

Mattia said he knows the new jury will do the right thing.

"They have to do something right. They'll do something right, I believe so," said Mattia.

The house is filled with pictures of Heather and her bedroom remains locked because her parents keep it as a memorial.

"Does it make you glad to see her everyday?" asked 10News' Mitch Blacher.

"Everyday. The first thing I see when I get up is Heather," said Mattia.

Heather's parents cannot bring themselves to the courthouse because they said it is too hard.

While Rices has admitted to pulling the trigger, Mattia said Miller is just as guilty.

"She lay on the floor, he shot her, took her money and left. How somebody could say he's not guilty ... I don't know," said Mattia.

Miller's retrial is scheduled for the end of September.