Opening arguments in the Melgar murder trial began early Wednesday.

Sandra Melgar, 57, stands accused of killing her husband of 32 years in December 2012, but, despite the evidence, she maintains her innocence.

RELATED: Dateline arrives in Houston to cover high school sweethearts murder trial

Prosecutors presented their first witness today – a crime scene investigator.  As the witness testified, the questioning prosecutor displayed photos of Jaime Melgar as he was found bound and stabbed to death in a closet at the home he shared with his wife.

As photos were displayed, Sandra erupted in sobs, wiping away tears at the sight of her deceased husband.

The prosecutor rebuked her display of emotion, and Judge Kelli Johnson ordered the defendant to maintain her composure during testimony.

Five years in the making, Sandra’s case garnered national attention – so much so, Dateline is in Houston to cover the trial, famous because of the weird circumstances of the crime:

Jaime and Sandra were discovered on the eve of their 32nd wedding anniversary, just before Christmas in 2012. Friends and relatives who came to the home to celebrate the couple found Jaime bound and stabbed in one closet, while Sandra was found bound in another – unharmed.

A year later, police arrested Sandra on a charge of murdering her husband and staging a home invasion.

However, those closest to the couple were in disbelief of the charges, especially since she  was found with her hands and ankles tied behind her back in a wedged-shut closet closed from the outside with a chair.

Court documents show authorities tried to file charges against Melgar the day after the crime, though she would not be arrested until a year later.

Melgar’s attorneys are using this fact as part of their case, which they say shows police targeted Sandra Melgar from day one, ignoring evidence possibly establishing her innocence – like a bloody fingerprint on the safe next to her husband’s body, which allegedly went without investigation – as well.

RELATED: Melgar murder trial begins with stunning defense allegations

Prosecutor Colleen Barrett admitted to the jury there was no motive in the case, saying the defendant “just brutally murdered her husband.”

Melgar’s case is expected to last for about a week.

She faces life in prison if convicted.