Updated 02/01/12 – 8:14 p.m.

WOODSTOCK, Ill. (CBS) — A McHenry County jury was unable to reach a verdict in the murder trial of a man accused in the 2002 murder of a Johnsburg teenager whose body was never found.

Jurors deliberated for about 12 hours over two days, but remained deadlocked on Wednesday as to whether Mario Casciaro, now 28, was guilty of killing 17-year-old Brian Carrick. They told the judge they would not be able to reach an agreement and the judge declared a mistrial.

Prosecutors said they intend to retry Casciaro. Assistant McHenry County State’s Atty. Michael Combs said the prosecution’s case won’t change.

LISTEN: WBBM Newsradio’s Bob Roberts reports

Carrick’s father, William Carrick, said he father is “encouraged” by the fact that prosecutors plan to try the case again.

“Next time, I’m hoping that the jury’s going to rule in our favor,” he said.

Defense attorney Brian Telander said Casciaro expected to be acquitted.

“He was surprised and he was very disappointed. He was very hopeful that they would find the state’s witnesses not credible, since every single one of them had been to the penitentiary and given inconsistent statements.”

After the mistrial was declared Wednesday, local residents were talking about the case at a local shop near the grocery store where Brian Carrick was last seen alive.

Pet Supply store owner Peggy King, said, “It’s very sad for the family, for both sides, actually, to really not have the correct information, no body. So, to get closure I think is really tough.”

But William Carrick told CBS 2’s Mike Parker, “I don’t understand what that closure thing is all about. I know I’m not going to see Brian again in this world, and that’s what I miss the most.”

Brian Carrick and Casciaro both worked at a grocery store co-owned by Casciaro’s family in far northwest suburban Johnsburg.

Carrick was a stock boy at the store, while Casciaro was his supervisor.

Brian Carrick (Credit: CBS)

Combs told the jury that Casciaro set into motion the events that led to Carrick’s disappearance. He allegedly dealt drugs for Casciaro and owed him money.

Prosecutors alleged that, on Dec. 20, 2002, Casciaro had a friend, Shane Lamb, try to collect the money from Carrick.

Lamb testified against Casciaro with a grant of immunity from prosecutors. He testified that he lost his temper with Carrick and punched him, knocking him out. But he said Casciaro told him to leave after the fight and that he didn’t know what happened to Carrick after that.

Police found the teenager’s blood in the cooler at the grocery store where the two worked, but they never located his body.

Prosecutors argued that, even if Casciaro wasn’t the one who delivered the fatal blows, he was responsible for setting Carrick’s murder in motion.