San Jose, Calif., police say a local woman with no criminal record replaced orange juice bottles in a Starbucks cold box with tainted ones - and they are puzzled about why she may have done it.

Ramineh Behbehanian, 50, will face charges of suspicion of poisoning and attempted murder, police said.

Image credit: San Jose Police Department

The Starbucks, located on the 6000 Block of Snell Avenue in South San Jose, Calif., was evacuated Monday evening after a customer spotted a woman switching bottles in the cold box at the front of the store with those in her bag, according to police.

As the witness was notifying Starbucks employees of the woman's suspicious activity, police said, the suspect apparently overheard the conversation and fled the scene abruptly. A Starbucks employee was able to record the license plate of the woman's car.

The San Jose Fire Department responded to the scene after Starbucks employees examined the bottles and found the contents had a toxic smell to them, police said.

The bottles were tested with hazardous materials equipment and were found to contain a mixture of isopropyl alcohol, or rubbing alcohol, police added.

Later that evening, police took Behbehanian into custody after she was found to be the owner of the car leaving the scene.

"Right now, we do not have any indication of further threats," Sgt. Jason Dwyer, a spokesman for the San Jose Police Department, told ABC News. "We believe she acted alone and, so far, we have no further information leading us to believe that she was a part of a group."

Behbehanian indicated that she planned to hire an attorney, police said, but they did not know if she had yet done so.

She was expected to be arraigned within the next 48 hours, Dwyer said, but a court date had not been set. In the meantime, Behbehanian was being held without bail at the Elmwood Complex Women's Facility.

Police were still investigating a motive for the alleged incident.

A spokesman for Starbucks, Zack Hutson, told ABC News that employees of the Snell Avenue Starbucks went above and beyond what they were supposed to do.

"Our partners are trained that safety is our No. 1 concern and, in instances like this, they did exactly the right thing in calling the police," Hutson said. "Our partners are always trained to monitor the store, including the cold case and lobby area, and to report any specious behavior."

Starbucks employees later emptied the contents of the rest of the cold case as a precautionary measure. Other Starbucks in the area were also warned to inspect their cold cases and to make sure everything was properly sealed.

"No one consumed the juice and, again, our partners and our customers did the right thing by acting quickly," said Hutson. "We destroyed the juice [and so did] our partner in the other area."